feat: refresh user mounts when removed from a group or circle that has associated team folders

[cristianscheid]

• Resolves: #

Summary

When a team folder is shared with a group or circle, removing a member currently leaves a stale entry for that folder in oc_mounts until their next login.

This PR refreshes the user's mounts (removing the stale entry) upon detecting the following events:

• OCP\Group\Events\UserRemovedEvent
• OCA\Circles\Events\CircleMemberRemovedEvent

To avoid refreshing mounts unnecessarily, the refresh only runs if the group/circle actually has a team folder associated with it.

The refresh logic mirrors what the files:mount:refresh command already does:
https://github.com/nextcloud/server/blob/master/apps/files/lib/Command/Mount/Refresh.php#L45

This PR depends on the following PR being merged first, which introduces methods to check whether a given group or circle has a team folder shared with it:

• feat(folder-manager): add methods to check if group or circle has associated team folders groupfolders#4884

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

[cristianscheid]

Converted to draft to wait for nextcloud/groupfolders#4884 to be merged first.