fix(files_sharing): 500 on /download link redirect

[ShGKme]

Summary

• Resolves: public share /download links crash
• Regression from: fix(files_sharing): make legacy downloadShare endpoint compatible with legacy behavior #56967
• Addition to: fix(files_sharing): Drop trailing '?' from public download redirect URL #59867
• Redirect URL has no trailing slash:
  • Generated: /public.php/dav/files/FLg5DZ3X69CNZfR?accept=zip
  • Should be: /public.php/dav/files/FLg5DZ3X69CNZfR/?accept=zip
  • See: https://github.com/nextcloud/3rdparty/blob/f7176e8becad6b9ef000422fc6039025b58dd2c9/sabre/dav/lib/DAV/Server.php#L576
  • This is also how the link is generated on the frontend

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

[ShGKme]

/backport to stable34

[ShGKme]

/backport to stable33

[ShGKme]

/backport to stable32

[ShGKme]

/backport to stable31

[ShGKme]

/backport! to stable31

[backportbot]

The backport to stable31 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable31
git pull origin stable31

# Create the new backport branch
git checkout -b backport/61015/stable31

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick 16db9265

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/61015/stable31

Error: Failed to check for changes with origin/stable31: No changes found in backport branch

---

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

[ShGKme]

• fixed a typo in a commit message

[ShGKme]

This change may not be needed on Nextcloud 32 and above.

• Ref: feat(dav): Enable chunked upload for public shares #52182

That PR (accidentally?) added support for /public.php/dav/files/TOKEN? links by changing the baseuri to just /public.php/dav/.

@provokateurin Was it intentional?

I'm unsure if we still need this change, or we officially support links without the trailing slash in dav...