Fix permission bug in search

What does this MR do?

Fix the permission inversion and possibly also wrong handling of empty non-null array in the search, that I added in !1522 (merged).

How confident are you it won't break things if deployed?

Quite sure, should be better than before at least

How to test

Steps a reviewer can take to verify that this MR does what it says it does e.g.

1. Checkout branch locally
2. Login as foodsaver
3. Check if the search in the topbar works
4. Login as orga
5. Check the search again

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• joined #foodsharing-beta channel at https://slackin.yunity.org
• added an entry to CHANGELOG.md (description, merge request link, username(s))
• Once your MR has been merged, you are responsible to update the #foodsharing-beta Slack channel about what has been changed here. They will test your work in different browsers, roles or other settings