fix: stabilize useWithdrawalRequests selectors to prevent unnecessary re-renders (#29597)

## **Description**

Inline `[]` fallbacks in `useWithdrawalRequests` selectors were creating
new array references on every render, triggering React-Redux's "Selector
unknown returned a different result" warning and causing unnecessary
re-renders in `PerpsProgressBar` on mount.

Fixed by replacing inline `[]` literals with module-level constants and
short-circuiting `.filter()` on empty arrays so selectors always return
the same reference.

**Performance impact:** FPS on Perps tab mount improved from 60→22 drops
down to a stable 60→57, nearly eliminating the frame drop entirely and
it doesn't take ~1 second for the Perps screen to show anymore

**NOTE**: Unrelated to these changes, there is a considerate amount of
frame drop when you're on the Perps home screen and from the UI
hydrating. The frames drop as low as 8 FPS. This happens in `main` and
this branch as well. Might be worth a follow up ticket

## **Changelog**

CHANGELOG entry:null

## **Related issues**

Fixes:

## **Manual testing steps**

```gherkin
Feature: Perps home screen mount

  Scenario: user opens the app with Perps hub tab visible
    Given the hub tabs A/B test is enabled
    And the user has no pending withdrawal requests

    When the app loads and PerpsProgressBar mounts
    Then no "Selector unknown returned a different result" warning appears in the console
    And the Perps tab renders without unnecessary re-renders
    And FPS remains at or above 57 during mount
```

## **Screenshots/Recordings**


https://github.com/user-attachments/assets/76f6b555-a949-4633-8d4c-aaffffb23f65

### **Before**


https://github.com/user-attachments/assets/4fb102b9-2dac-48c6-9b10-bbe6316825d2

### **After**


https://github.com/user-attachments/assets/4c6688dd-159c-4e9e-89ef-c298de8bc34c

## **Pre-merge author checklist**

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- [x] I've followed [MetaMask Contributor
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Not required for external contributors.

#### Performance checks (if applicable)

- [ ] I've tested on Android
  - Ideally on a mid-range device; emulator is acceptable
- [ ] I've tested with a power user scenario
- Use these [power-user
SRPs](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/edit-v2/401401446401?draftShareId=9d77e1e1-4bdc-4be1-9ebb-ccd916988d93)
to import wallets with many accounts and tokens
- [ ] I've instrumented key operations with Sentry traces for production
performance metrics
- See [`trace()`](/app/util/trace.ts) for usage and
[`addToken`](/app/components/Views/AddAsset/components/AddCustomToken/AddCustomToken.tsx#L274)
for an example

For performance guidelines and tooling, see the [Performance
Guide](https://consensyssoftware.atlassian.net/wiki/spaces/TL1/pages/400085549067/Performance+Guide+for+Engineers).

## **Pre-merge reviewer checklist**

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- [x] I confirm that this PR addresses all acceptance criteria described
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<!-- CURSOR_SUMMARY -->
---

> [!NOTE]
> **Low Risk**
> Low risk performance-only change: replaces inline empty-array
fallbacks with stable module constants to avoid React-Redux selector
warnings and unnecessary re-renders; no business logic or API behavior
changes expected.
> 
> **Overview**
> Prevents unnecessary re-renders in `useWithdrawalRequests` by
replacing inline `[]` selector fallbacks with module-level
`EMPTY_WITHDRAWAL_REQUESTS`/`EMPTY_TX_HASHES` constants and
short-circuiting the withdrawal `.filter()` when there’s no selected
address or the list is empty.
> 
> This makes selector outputs stable across renders (eliminating the
“selector returned a different result” warning) while keeping the
displayed/polled withdrawal logic unchanged.
> 
> <sup>Reviewed by [Cursor Bugbot](https://cursor.com/bugbot) for commit
e020446. Bugbot is set up for automated
code reviews on this repo. Configure
[here](https://www.cursor.com/dashboard/bugbot).</sup>
<!-- /CURSOR_SUMMARY -->

Author: vinnyhoward

app/components/UI/Perps/hooks/useWithdrawalRequests.ts

@@ -34,6 +34,9 @@ interface UseWithdrawalRequestsResult {
   refetch: () => Promise<void>;
 }
 
+const EMPTY_WITHDRAWAL_REQUESTS: WithdrawalRequest[] = [];
+const EMPTY_TX_HASHES: string[] = [];
+
 const WITHDRAWAL_POLL_INTERVAL_MS = 5000;
 const WITHDRAWAL_SEARCH_BUFFER_MS = 60000;
 
@@ -56,8 +59,10 @@ export const useWithdrawalRequests = (
 
   const allWithdrawals = useStableArray(
     usePerpsSelector((state) => {
-      const withdrawals = state?.withdrawalRequests || [];
-      if (!selectedAddress) return [];
+      const withdrawals =
+        state?.withdrawalRequests ?? EMPTY_WITHDRAWAL_REQUESTS;
+      if (!selectedAddress || withdrawals.length === 0)
+        return EMPTY_WITHDRAWAL_REQUESTS;
       return withdrawals.filter(
         (req) =>
           req.accountAddress?.toLowerCase() === selectedAddress.toLowerCase(),
@@ -79,7 +84,7 @@ export const useWithdrawalRequests = (
     (state) => state?.lastCompletedWithdrawalTimestamp ?? null,
   );
   const lastCompletedTxHashes = usePerpsSelector(
-    (state) => state?.lastCompletedWithdrawalTxHashes ?? [],
+    (state) => state?.lastCompletedWithdrawalTxHashes ?? EMPTY_TX_HASHES,
   );
 
   const initialFetchDoneRef = useRef(false);