fix(macos): Get actual user home directory correctly

[claucambra]

Resolves

The sync folder location picker defaulting to the library/containers path

Summary

This change ensures the current user's actual home folder is presented for syncing

https://developer.apple.com/documentation/foundation/nshomedirectory%28%29?language=objc
https://developer.apple.com/library/archive/documentation/General/Conceptual/MOSXAppProgrammingGuide/AppRuntime/AppRuntime.html

Checklist

• Sign-off message is added to all commits.
• The commit history is clean with no merge commits.
  • How to rebase your commits
  • How to squash commits with rebase
• Uploaded screenshots from before and after for UI changes.
• Test(s) added to branch, with before/after results included in PR description, for performance improvements where applicable.
• Documentation has been updated or is not required.
• Backports requested where applicable (critical bugfixes).
• Labels added where applicable (bug/enhancement).
• Milestone added for target version.

AI (if applicable)

• The content of this PR was partly or fully generated using AI
  • I have read the guidelines for AI-assisted contributions.
  • I have read Nextcloud's AI Contribution Policy.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Artifact containing the AppImage: nextcloud-appimage-pr-10571.zip

Digest: sha256:5577677d5251b58cb3e2c412d9c7d5b548d1b4c736db8eb385e908dfb4d856c8

To test this change/fix you can download the above artifact file, unzip it, and run it.

Please make sure to quit your existing Nextcloud app and backup your data.

[Rello]

/backport to stable-34.0

[claucambra]

/backport to stable-33.0