Cache the manager app id sent in UpdateLocalDeviceMetadata() (which is called
every time the service is started up). The manager app id and the account name (which is stored in the already cached Metadata) is needed to fetch the credentials used during connection authentication.
See [Anay's one pager](https://docs.google.com/document/d/1bffDNH-he4qteN3MxkbUz-P2xFoIniO088sRiTc-kkE/edit?usp=sharing) for more details.
PiperOrigin-RevId: 572067964