fix(ocp): Fix reference of dashboard IAPIWidget::getItems from WidgetItem

[ChristophWurst]

Summary

The ref goes to /dev/null on master. It now points to an existent method.

TODO

• Fix PHPDoc

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)

[ChristophWurst]

🏓 for review

[ChristophWurst]

/backport to stable27

[ChristophWurst]

/backport to stable26

[ChristophWurst]

/backport to stable25

[backportbot-nextcloud]

The backport to stable25 failed. Please do this backport manually.

# Switch to the target branch and update it
git checkout stable25
git pull origin stable25
# Create the new backport branch
git checkout -b fix/foo-stable25
# Cherry pick the change from the commit sha1 of the change against the default branch# This might cause conflicts. Resolve them.
git cherry-pick abc123
# Push the cherry pick commit to the remote repository and open a pull request
git push origin fix/foo-stable25

More info at https://docs.nextcloud.com/server/latest/developer_manual/getting_started/development_process.html#manual-backport