fix unencrypted_size for folders when scanning the filesystem with encryption enabled

[icewind1991]

To test:

• setup an instance with encryption

• create folder test and write some files into it

• "accidentally" mess up the unencrypted_size for the folder with

  update oc_filecache set unencrypted_size = 100 where name = 'test';

• run occ files:scan --all in an attempt to repair it

• check if the folder size is reported correctly

[PVince81]

is this related / should this be linked with #25283 which has the whole discussion about unencrypted_size ? also there might be people there who could test this PR ?

[camilasan]

Any plans to merge and backport this to 25 @icewind1991 @come-nc ?

[icewind1991]

/backport to stable26

[icewind1991]

/backport to stable25

[backportbot-nextcloud]

The backport to stable26 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable26
git pull origin/stable26

# Create the new backport branch
git checkout -b fix/foo-stable26

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable26

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[backportbot-nextcloud]

The backport to stable25 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable25
git pull origin/stable25

# Create the new backport branch
git checkout -b fix/foo-stable25

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts. Resolve them.
git cherry-pick abc123

# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable25

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport

[icewind1991]

/backport to stable26