fix(auth): Update authtoken activity selectively

[ChristophWurst]

• Addresses Avoid updating the same oc_authtoken row twice #45026 (comment)

Summary

We want to update the authtoken.last_activity when we write authtoken.last_check. But we don't want the activity to update for updates of any other fields, when the token is not used.

How to test

1. Create an auth token via the personal security settings
2. Open the authtoken database table, set last_activity=0 for the latest row
3. Change the name of the auth token

master: last activity changes to now
here: last activity stays at 54 years ago

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)