Fix the ScanFiles job to not trigger scans of root directory for every single user

[akhil1508]

• Resolves [Bug]: ScanFiles job triggers a scan of the root storage for each and every user #61510
• Possibly resolves
  • [Bug]: ScanFiles never performed and slow with big tables #40018
  • [Bug]: Nextcloud Files background job ScanFiles eats up all RAM #45042
  • Query on oc_filecache uses wrong index - Cron job runs very long #24401

Summary

• When '' is passed getMounts returns home::username and local:/var/www/data mounts and both of these get scanned
• This manages to scan the appdata folder too for each and every user adding significant delays to a job that should be quick for 500 users at one time
• This method seems the same as the one used in occ files:scan username --unscanned and there the path resolves to /username and not ''

TODO

• ...

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)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI

[provokateurin]

Makes sense 👍

[provokateurin]

/backport to stable34

[provokateurin]

/backport to stable33

[provokateurin]

/backport to stable32

[provokateurin]

@akhil1508 please don't update the branch, unless there are actual conflicts. This requires us to re-approve and restart CI, resulting in delays for merging the PR.

[akhil1508]

please don't update the branch, unless there are actual conflicts. This requires us to re-approve and restart CI, resulting in delays for merging the PR.

@provokateurin got it, apologies!