Upgrade @metamask/messenger to version 2.0.0

A new major version of `@metamask/messenger`, 2.0.0, is now available. This issue has been assigned to you and your team because you code-own this package in the `core` repo. If this package is present in this project, please prioritize upgrading it soon to unblock new features and bugfixes.

Search the repository's package manifests and lockfiles for @metamask/messenger to determine whether this project uses it. If present, update the dependency to 2.0.0, refresh the lockfile if needed, and run the relevant dependency or project checks to confirm the upgrade works and unblocks the newer package.

Written by the indexing model from the issue text.