fix(files_external): ignore unsatisfied optional dependencies

[jplitza]

• Resolves: [Bug]: 'Invalid storage backend "smb"' when only smbclient is installed #54047

Summary

Fix setup of external storage with unsatisfied optional dependencies (which were introduced in #52681)

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)

[jplitza]

I simply cannot understand how my changes would affect the failing tests ("files_sharing: Note to recipient -> shows an existing note when editing a share" timeout), but re-running the failing jobs twice did not fix them…

[skjnldsv]

@jplitza ignore it, it's very unstable at the moment :)
Thanks for the PR!

[come-nc]

Looks fine I think but I’d like @icewind1991 to check the logic.

[github-actions]

Hello there,
Thank you so much for taking the time and effort to create a pull request to our Nextcloud project.

We hope that the review process is going smooth and is helpful for you. We want to ensure your pull request is reviewed to your satisfaction. If you have a moment, our community management team would very much appreciate your feedback on your experience with this PR review process.

Your feedback is valuable to us as we continuously strive to improve our community developer experience. Please take a moment to complete our short survey by clicking on the following link: https://cloud.nextcloud.com/apps/forms/s/i9Ago4EQRZ7TWxjfmeEpPkf6

Thank you for contributing to Nextcloud and we hope to hear from you soon!

(If you believe you should not receive this message, you can add yourself to the blocklist.)

[susnux]

/backport to stable33

[susnux]

/backport to stable32

[susnux]

/backport to stable33

[susnux]

/backport to stable32

[backportbot]

The backport to stable32 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable32
git pull origin stable32

# Create the new backport branch
git checkout -b backport/54048/stable32

# Cherry pick the change from the commit sha1 of the change against the default branch
# This might cause conflicts, resolve them
git cherry-pick 0f4d6b80

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/54048/stable32

Error: Failed to push branch backport/54048/stable32: remote: Invalid username or token. Password authentication is not supported for Git operations.
fatal: Authentication failed for 'https://github.com/nextcloud/server.git/'

---

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