refactor: migrate assets controllers messenger

[mikesposito]

Explanation

This PR migrates all remaining assets controllers to @metamask/messenger instead of @metamask/base-controller. This is part of a larger effort to migrate all controllers to use @metamask/messenger.

References

• Related to Implement messenger delegation #5626

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 communicated my changes to consumers by updating changelogs for packages I've changed, highlighting breaking changes as necessary
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes

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Note

Migrates remaining assets controllers and tests to the new @metamask/messenger API and base-controller/next, updates metadata flags, and consolidates the changelog breaking note.

• BREAKING: Messenger migration
  • Replace RestrictedMessenger from @metamask/base-controller with Messenger from @metamask/messenger in MultichainAssetsController, MultichainBalancesController, NftDetectionController, RatesController, and TokenSearchDiscoveryDataController.
  • Switch controller internals from messagingSystem to messenger (publish/subscribe/call).
• Base Controller vNext
  • Update imports to @metamask/base-controller/next; adopt StateMetadata and deriveStateFromMetadata with includeInDebugSnapshot.
  • Update controller metadata to use includeInDebugSnapshot instead of anonymous.
• Tests
  • Refactor tests to construct a root Messenger with namespaces and delegate allowed actions/events; remove legacy getRestricted usage where applicable.
• Changelog
  • Consolidate and expand the breaking-change entry to reference all controller migrations and related PRs.

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[mcmire]

One thing that Cursor noticed.

[mcmire]

Hmm, it does seem that we need a parent option here.