chore: export controller messenger type to index

[Bigshmow]

Explanation

We are not explicitly exporting the TokenSearchDiscoveryControllerMessenger type from package index and therefor consumers are forced to import from the common js module.

References

Needed to resolve a comment in related to these types of imports: MetaMask/metamask-mobile#13111

Changelog

@metamask/token-search-discovery-controller

• Added: export TokenSearchDiscoveryControllerMessenger type from index

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
• I've prepared draft pull requests for clients and consumer packages to resolve any breaking changes