fix/2555: share delete and public link access

[samin-z]

apply share delete and public link access respecting to limitations

[benjaminfrueh]

@samin-z as we just discussed, this could maybe be simplified.
The public controller should not use the user session as it should not require a user and only use the token (and optionally a password) to authenticate.

I think the easiest way would be to get the sender user from the share and simply validate this user with sharingDisabledForUser() - I didn't test that though.

The files app does the public link checks checks in https://github.com/nextcloud/server/blob/master/apps/files_sharing/lib/Controller/ShareController.php#L263
Maybe it makes sense for tables to also check if the share sender user is disabled, and also deny access then, like the files_app already does.

[samin-z]

/backport! to stable1.0

[backportbot]

The backport to stable1.0 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable1.0
git pull origin stable1.0

# Create the new backport branch
git checkout -b backport/2556/stable1.0

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick a9424787 da998666 b8a1e64d

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/2556/stable1.0

Error: Failed to check for changes with origin/stable1.0: No changes found in backport branch

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.

[samin-z]

/backport! to stable0.9

[backportbot]

The backport to stable0.9 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable0.9
git pull origin stable0.9

# Create the new backport branch
git checkout -b backport/2556/stable0.9

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick a9424787 da998666 b8a1e64d

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/2556/stable0.9

Error: Failed to check for changes with origin/stable0.9: No changes found in backport branch

---

Learn more about backports at https://docs.nextcloud.com/server/stable/go.php?to=developer-backports.