feat(identity): sync address book contacts

[fabiobozzo]

Explanation

The current implementation of MetaMask's address book (contacts) lacks the ability to synchronize between devices. While we recently implemented this capability for accounts using encrypted user storage, the address book remained local to each device.
This PR implements backup-and-sync functionality for the address book controller, similar to what was already implemented for the accounts controller.

Implementation notes

1. Creates a dedicated integration in the profile-sync-controller package with:

• Type definitions for address book storage entries
• Conversion utilities between controller and storage formats
• Sync logic to handle bidirectional synchronization

2. Event subscriptions to trigger syncs on contact changes
3. Updates the UserStorageController to properly handle address book data

References

Needed by: MetaMask/metamask-extension#32632
Depends on: #5779

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

[socket-security]

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