fix: max mUSD conversion displays wrong value (#29175)

## **Description**

Fixes the max mUSD conversion showing an inflated receive amount. Relay
previously charged a fee and reimbursed it on the destination side; they
have since stopped charging the fee, so our compensating adjustment now
over-reports the received value.

Bumps `@metamask/transaction-pay-controller` from `^19.1.1` to
`^19.2.1`, which stops double-counting the subsidised fee in Relay quote
target amounts, and patches the installed package to rename the Relay
gasless feature flag from `executeEnabled` to `gaslessEnabled` so older,
known-broken versions cannot be re-enabled by the flag (which predates
per-version gating).

## **Changelog**

CHANGELOG entry: Fixed max mUSD conversion displaying an inflated
receive amount.

## **Related issues**

Fixes: #29173

## **Manual testing steps**

```gherkin
Feature: Max mUSD conversion displays correct value

  Scenario: user converts max USDC to mUSD
    Given a 7.74 build with this patch installed
    And the user holds some USDC
    When the user taps max on the mUSD conversion screen
    Then the displayed mUSD receive amount matches the USDC balance (no inflation)
```

## **Screenshots/Recordings**

### **Before**

### **After**

## **Pre-merge author checklist**

- [x] I've followed [MetaMask Contributor
Docs](https://github.com/MetaMask/contributor-docs) and [MetaMask Mobile
Coding
Standards](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/CODING_GUIDELINES.md).
- [x] I've completed the PR template to the best of my ability
- [x] I've included tests if applicable
- [x] I've documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [x] I've applied the right labels on the PR (see [labeling
guidelines](https://github.com/MetaMask/metamask-mobile/blob/main/.github/guidelines/LABELING_GUIDELINES.md)).
Not required for external contributors.

## **Pre-merge reviewer checklist**

- [ ] I've manually tested the PR (e.g. pull and build branch, run the
app, test code being changed).
- [ ] I confirm that this PR addresses all acceptance criteria described
in the ticket it closes and includes the necessary testing evidence such
as recordings and or screenshots.

<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Medium Risk**
> Updates core transaction/pay controller dependencies and applies a
patch that changes which remote feature flag enables Relay gasless
execution, which could affect pay/quote flows if flag configuration or
dependency behavior differs from expectations.
> 
> **Overview**
> Fixes an inflated “max” conversion receive amount by bumping
`@metamask/transaction-pay-controller` to `^19.2.1` (and aligning
related controller versions via `yarn.lock`/resolutions).
> 
> Adds a patch to `@metamask/transaction-pay-controller` that switches
the Relay enablement check from
`confirmations_pay.payStrategies.relay.executeEnabled` to
`...relay.gaslessEnabled`, preventing older broken builds from being
re-enabled by the previous flag name.
> 
> Separately removes the locally-defined `MANTLE` entry from
`NETWORK_CHAIN_ID` in `customNetworks.tsx` (relying on `CHAIN_IDS` for
it instead).
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
67e50b9. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: matthewwalsh0

app/util/networks/customNetworks.tsx

@@ -391,7 +391,6 @@ export const NETWORK_CHAIN_ID: {
   readonly TEMPO_MAINNET: '0x1079';
   readonly CHILIZ: '0x15b38';
   readonly STABLE_MAINNET: '0x3dc';
-  readonly MANTLE: '0x1388';
 } & typeof CHAIN_IDS = {
   FLARE_MAINNET: '0xe',
   SONGBIRD_TESTNET: '0x13',
@@ -438,7 +437,6 @@ export const NETWORK_CHAIN_ID: {
   TEMPO_MAINNET: '0x1079',
   CHILIZ: '0x15b38',
   STABLE_MAINNET: '0x3dc',
-  MANTLE: '0x1388',
   ...CHAIN_IDS,
 };
 

package.json

@@ -198,7 +198,9 @@
     "expo-web-browser@npm:~14.0.2": "patch:expo-web-browser@npm%3A14.0.2#~/.yarn/patches/expo-web-browser-npm-14.0.2-98d00ce880.patch",
     "@metamask/messenger@^0.3.0": "^1.0.0",
     "@metamask/accounts-controller": "^37.2.0",
-    "@metamask/profile-sync-controller": "^28.0.2"
+    "@metamask/profile-sync-controller": "^28.0.2",
+    "@metamask/transaction-controller@^63.0.0": "^64.2.0",
+    "@metamask/transaction-controller@^63.3.1": "^64.2.0"
   },
   "dependencies": {
     "@braze/react-native-sdk": "patch:@braze/react-native-sdk@npm%3A19.1.0#~/.yarn/patches/@braze-react-native-sdk-npm-19.1.0-076-reactmoduleinfo.patch",
@@ -325,7 +327,7 @@
     "@metamask/superstruct": "^3.2.1",
     "@metamask/swappable-obj-proxy": "^2.1.0",
     "@metamask/transaction-controller": "^64.2.0",
-    "@metamask/transaction-pay-controller": "^19.1.1",
+    "@metamask/transaction-pay-controller": "^19.2.1",
     "@metamask/tron-wallet-snap": "^1.25.2",
     "@metamask/utils": "^11.11.0",
     "@myx-trade/sdk": "^0.1.265",

patches/@metamask+transaction-pay-controller+19.2.1.patch

@@ -0,0 +1,53 @@
+diff --git a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.cjs b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.cjs
+index 66884ed..d475de2 100644
+--- a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.cjs
++++ b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.cjs
+@@ -238,7 +238,8 @@ exports.getPayStrategiesConfig = getPayStrategiesConfig;
+ function isRelayExecuteEnabled(messenger) {
+     const state = messenger.call('RemoteFeatureFlagController:getState');
+     const featureFlags = state.remoteFeatureFlags?.confirmations_pay ?? {};
+-    return featureFlags.payStrategies?.relay?.executeEnabled ?? false;
++    // Renamed from `executeEnabled` so the flag cannot re-enable the flow on older broken versions (predates version support).
++    return featureFlags.payStrategies?.relay?.gaslessEnabled ?? false;
+ }
+ exports.isRelayExecuteEnabled = isRelayExecuteEnabled;
+ /**
+diff --git a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.mjs b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.mjs
+index c8b2f8a..5ab03a9 100644
+--- a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.mjs
++++ b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.mjs
+@@ -232,7 +232,7 @@ export function getPayStrategiesConfig(messenger) {
+ export function isRelayExecuteEnabled(messenger) {
+     const state = messenger.call('RemoteFeatureFlagController:getState');
+     const featureFlags = state.remoteFeatureFlags?.confirmations_pay ?? {};
+-    return featureFlags.payStrategies?.relay?.executeEnabled ?? false;
++    return featureFlags.payStrategies?.relay?.gaslessEnabled ?? false;
+ }
+ /**
+  * Get the origin gas overhead to include in Relay quote requests
+diff --git a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.cts b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.cts
+index 0ef444d..0538026 100644
+--- a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.cts
++++ b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.cts
+@@ -41,7 +41,7 @@ export type PayStrategiesConfigRaw = {
+     across?: AcrossConfigRaw;
+     relay?: {
+         enabled?: boolean;
+-        executeEnabled?: boolean;
++        gaslessEnabled?: boolean;
+         originGasOverhead?: string;
+         pollingInterval?: number;
+         pollingTimeout?: number;
+diff --git a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.mts b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.mts
+index e08336e..8dd8f42 100644
+--- a/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.mts
++++ b/node_modules/@metamask/transaction-pay-controller/dist/utils/feature-flags.d.mts
+@@ -41,7 +41,7 @@ export type PayStrategiesConfigRaw = {
+     across?: AcrossConfigRaw;
+     relay?: {
+         enabled?: boolean;
+-        executeEnabled?: boolean;
++        gaslessEnabled?: boolean;
+         originGasOverhead?: string;
+         pollingInterval?: number;
+         pollingTimeout?: number;