Very minor tweaks to include with 'Birne'

Best reviewed commit by commit

What does this MR do?

Minor UI adjustments to a few places. See the individual commits for details.

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

100% for everything aside the draft-switching, but confident enough for that one too.

How to test

Mostly just minor UI changes, so before/after for those screens.

Message drafts:

1. go to messages page
2. write content into the "answer" box
3. switch to another conversation by clicking on it

you should see a popup

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
• use "state:" labels to track this MR's state until it was beta tested
• added an entry to CHANGELOG.md
• add a short text that can be used in the release notes
• Once your MR has been merged, you are responsible to create a testing issue in Beta Testing Repo:
  • 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.

RELEASE NOTES

Wenn ihr in der Ansicht aller Chat-Nachrichten eine Antwort schreibt und vor dem Absenden rechts eine andere Unterhaltung auswählt, gibt es nun einen Hinweis darauf und die Möglichkeit, den Text zu verwerfen (z.B. weil er nicht mehr zu der neuen Unterhaltung passt). Wenn ihr den Text wie zuvor automatisch übertragen wollt: einfach die Hinweismeldung abbrechen :)