[stable31] fix(public-share): do not init user config for public shares

[susnux]

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI

[susnux]

/backport to stable30

[susnux]

/backport to stable32

[susnux]

/compile

[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/3696/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 b8c12709 d040e2c4

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/3696/stable32

Error: Failed to check for changes with origin/stable32: No changes found in backport branch

---

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

[susnux]

/backport b8c1270 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/3696/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 b8c12709

# Push the cherry pick commit to the remote repository and open a pull request
git push origin backport/3696/stable32

Error: Failed to check for changes with origin/stable32: No changes found in backport branch

---

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

[susnux]

ok stable32 not affected