fix: token detection during account change

[bergeron]

Explanation

During account change, the token detection trigger was guarded by the useTokenDetection setting. But on mainnet, detection should run against the static token list even if the setting is disabled. So remove the guard.

I also removed the account change logic from PreferencesController:stateChange. It seemed redundant because AccountsController:selectedAccountChange already handles it fine in my testing.

References

MetaMask/metamask-extension#23798

Changelog

@metamask/assets-controllers

• FIXED: Token detection during account change

Checklist

• I've updated the test suite for new or updated code as appropriate
• I've updated documentation (JSDoc, Markdown, etc.) for new or updated code as appropriate
• I've highlighted breaking changes using the "BREAKING" category above as appropriate

[bergeron]

Closed in favor of #4133