Removed role from slot modal again

What does this MR do?

The word "role" is currently used in several places. There is an opinion in the beta testing working group that this term is confusing in the context of the slot. However, since there is no proposal to rename this term uniformly in all places, I have decided to remove it for the time being until there is a uniform proposal as an issue.

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

Links to related issues

https://beta.foodsharing.de/region?bid=734&sub=forum&tid=230869

How to test

Screenshots (if applicable)

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
• 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
• added a short text in the release notes to /release-notes/YYYY-MM.md
• Once your MR has been merged, you are responsible to create a testing issue in the Beta Testing forum: https://foodsharing.de/region?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.