refactor(ramps): use bottom sheet modal for ramp region selection

[georgeweiler]

Description

This PR refactors the ramp aggregator region modal to use the new bottom sheet navigation pattern.

Changelog

CHANGELOG entry:

Related issues

Fixes:

Manual testing steps

Feature: my feature name

  Scenario: user [verb for user action]
    Given [describe expected initial app state]

    When user [verb for user action]
    Then [describe expected outcome]

Screenshots/Recordings

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After

Pre-merge author checklist

• I’ve followed MetaMask Contributor Docs and MetaMask Mobile Coding Standards.
• 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 format if applicable
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---

Note

Replaces inline region modal with a bottom-sheet RegionSelectorModal, updates BuildQuote to navigate to it and react to region changes, adds routing, and updates tests and deposit modal list rendering.

• Ramp Aggregator:
  • Replace RegionModal with bottom-sheet RegionSelectorModal (components/RegionSelectorModal/*).
  • BuildQuote: navigate to region selector via createRegionSelectorModalNavigationDetails; remove local region modal state/handlers.
    • Add effects to reset amount on selectedRegion change and to auto-switch fiat currency to region default when applicable.
• Navigation/Routes:
  • Add Routes.RAMP.MODALS.REGION_SELECTOR and register screen in routes/index.tsx.
• Deposit:
  • Deposit/RegionSelectorModal: switch to ListItemSelect, simplify styles, and remove extra scrolling flags.
• Tests/Snapshots:
  • Update BuildQuote.test.tsx to assert navigation to RampRegionSelectorModal instead of directly setting region.
  • Refresh related snapshots to reflect new modal structure.

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[github-actions]

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[cursor]

Bug: Infinite Loop in useEffect Dependencies

The useEffect (lines 229-258) includes selectedFiatCurrencyId in its dependencies and updates it, which can lead to an infinite loop or redundant executions. This also introduces a race condition with queryDefaultFiatCurrency and triggers fiat currency updates on mount or other dependency changes, unlike the previous explicit region selection.

 

[cursor]

Bug: Modal Analytics Location Property Misconfigured

The RegionSelectorModal hard-codes the analytics location property to 'Amount to Buy Screen'. This results in incorrect analytics data when the modal is used in a sell flow, as the location should dynamically reflect whether it's a buy or sell transaction.