feat: update ramp data flow to fetch cryptos before payment methods (#14437)

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## **Description**

This is a UX upgrade to the ramp flow. It swaps the importance of the
payment method and crypto.

- removes payment method step from first time flow and after region
change
- auto-selects the payment method
- shows all cryptos in the list
- switches payment method to a valid one if the chosen one doesn't
support the new selected crypto


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## **Related issues**

Fixes:

## **Manual testing steps**

1. reset ramp region in settings, then visit ramps experience. confirm
that payment method selection page is removed
2. choose a payment with low token-availability (like paypal-staging).
then pick a token you know is unsupported (like SNX). Confirm that the
payment method is changed
3. confirm that various other similar user interactions such as changing
region, crypto, fiat and payment method always lead to an expected
result without error.


## **Screenshots/Recordings**

Video demonstration of the feature:
https://www.loom.com/share/fe29b773bb8f46afab8c4a6dadfc59ba


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before and after of your change. -->

### **Before**

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### **After**

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## **Pre-merge author checklist**

- [ ] 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).
- [ ] I've completed the PR template to the best of my ability
- [ ] I’ve included tests if applicable
- [ ] I’ve documented my code using [JSDoc](https://jsdoc.app/) format
if applicable
- [ ] 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.

Author: georgeweiler

CHANGELOG.md

@@ -10,6 +10,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 ### Added
 
 - feat(multi-srp): enable multi-srp in main and beta ([#14558](https://github.com/MetaMask/metamask-mobile/pull/14558))
+- feat(ramp): Update ramp data flow to fetch cryptos before payment methods ([#14437](https://github.com/MetaMask/metamask-mobile/pull/14437))
 - feat(bridge): add destination account picker ([#14656](https://github.com/MetaMask/metamask-mobile/pull/14656))
 - feat(bridge): add Solana assets to bridge token pickers ([#14365](https://github.com/MetaMask/metamask-mobile/pull/14365))
 - feat: add AppMetadataController controller ([#14513](https://github.com/MetaMask/metamask-mobile/pull/14513))