fix: prevent infinite provider alternation when all providers return empty payment methods

[saustrie-consensys]

Description

When a user selects a token (e.g. SOL) where multiple providers claim static support via supportedCryptoCurrencies but all return empty payment methods from the API, the auto-switch effect in BuildQuote enters an infinite loop — cycling between providers every ~370ms.

1. What is the reason for the change? The isTokenUnavailable effect silently switches to the next provider that statically supports the token, but never checks whether that candidate was already tried. When all candidates fail, it cycles back to the first one endlessly.

2. What is the improvement/solution? Track which providers have already been attempted for the current token via a ref (triedProvidersRef). Skip already-tried providers in the providers.find() call. Once all candidates are exhausted, fall through to the Token Not Available modal. The set resets when the token changes.

Changelog

CHANGELOG entry: null

Related issues

Fixes: https://consensyssoftware.atlassian.net/browse/TRAM-3435

Manual testing steps

Feature: Provider auto-switch does not loop infinitely

  Scenario: User selects a token where all providers return empty payment methods
    Given the user is on the Build Quote screen
    And the provider was auto-selected by the system (not manually chosen)
    And the user is in US-CA region

    When the user changes the buy token from ETH to SOL
    Then the system tries each provider that claims SOL support at most once
    And after exhausting all candidates, the Token Not Available modal is shown
    And the provider does NOT alternate rapidly between Robinhood and Moonpay

  Scenario: User selects a token where an alternative provider has payment methods
    Given the user is on the Build Quote screen
    And the provider was auto-selected by the system

    When the user changes to a token unsupported by the current provider
    And another provider supports the token with valid payment methods
    Then the system silently switches to that provider
    And no modal is shown

Screenshots/Recordings

Before

https://www.loom.com/share/ef3f1307805646478e9e6ae3aa8a088a

After

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✅ E2E Fixture Validation — Schema is up to date
16 value mismatches detected (expected — fixture represents an existing user).
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Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
88.9% Coverage on New Code
0.0% Duplication on New Code

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