Upgrade @metamask/earn-controller to version 12.0.0

A new major version of `@metamask/earn-controller`, 12.0.0, 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.

Check the project's dependency manifests and lockfiles to confirm whether @metamask/earn-controller is present and identify its current version. Review the package's integration points and existing checks, then update the dependency and verify that the mobile project still builds and its relevant tests pass.

Written by the indexing model from the issue text.