Upgrade @metamask/multichain-account-service to version 5.0.0

A new major version of `@metamask/multichain-account-service`, 5.0.0, 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.

Start by checking the project's dependency manifests for @metamask/multichain-account-service and confirming whether it is present. Update the dependency to version 5.0.0, refresh the relevant lockfile, and run the project's dependency or validation checks to confirm the upgrade is complete.

Written by the indexing model from the issue text.