Restore size and unshared columns for BTRFS snapshots

[ienzo]

Is your feature request related to a problem? Please describe.

In Linux Mint 20.3, Timeshift showed data on size and unshared size for BTRFS snapshots. This was removed for some reason I don't quite understand. In issue #10 "Size shared and unshared BTRFS snapshots missing in GUI," it was mentioned this feature was removed.

Describe the solution you'd like

I would like to see this feature returned. I deeply rely on this data as it helps me decide when to delete on-demand snapshots.

Additional context

This is how it looked like before:

[Fantu]

duplicate of #47

[tpraxl]

See PR #94 that is supposed to restore the columns on systems with enabled qgroups.
I am currently waiting for feedback on the PR.

[github-actions]

This issue has been automatically marked as stale because it has not had
any activity in over 2 years.

If this issue is still relevant:

• Please test on a current version of this package.
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[jondo]

This still is valid for version 25.12.4.