Reduce redundancies in permission checks (StoreRestController)

What does this MR do?

Adds a function for handling certain http exceptions to reduce redundancies.

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

I tried to work carefully, but changes like this are always error-prone. Thorough review required.

Links to related issues

...as far as I know we neither have nor need issues for general code quality...

How to test

Check if the affected api endpoints are still restricted like they where before.

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• set a "for:" label to indicate who will be affected by this change
• used "state:" labels to track this MR's state until it was beta tested
• added to the next milestone (see https://gitlab.com/foodsharing-dev/foodsharing/-/milestones, unless it has a "for:Dev" label)
• added an entry to CHANGELOG.md
• Once your MR has been merged, you are responsible to create a testing issue in the Beta Testing forum: https://foodsharing.de/?page=bezirk&bid=734&sub=forum. Please change the MRs label to "state:Beta testing".
  • Consider writing a detailed description in German.
  • Describe in a few sentences, what should be tested from a user perspective.
  • Also mention different settings (e.g. different browsers, roles, ...) how this change can be tested.
  • Be aware, that also non technical people should understand.