fix(files_external): ignore deprecated backends

[leftybournes]

• Resolves: #

Summary

Deprecated external storage backends used to be ignored but are being shown again. This fixes it so that they're ignored.

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

[joshtrichards]

Any idea when this changed? It's been like this for awhile from what I can tell.

[leftybournes]

@joshtrichards

It changed in stable33 during the vue migration. It used to be ignored before that.

https://github.com/nextcloud/server/blob/stable32/apps/files_external/templates/settings.php#L109-L111

[leftybournes]

/backport to stable34

[leftybournes]

/backport to stable33

[backportbot]

The backport to stable33 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable33
git pull origin stable33

# Create the new backport branch
git checkout -b backport/61568/stable33

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick e71d3e51

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/61568/stable33

Error: Failed to check for changes with origin/stable33: No changes found in backport branch

---

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

[leftybournes]

/backport to stable33

[backportbot]

The backport to stable33 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable33
git pull origin stable33

# Create the new backport branch
git checkout -b backport/61568/stable33

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick e71d3e51

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/61568/stable33

Error: Failed to check for changes with origin/stable33: No changes found in backport branch

---

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