Fix autocompletion for login form

What does this MR do?

The MR fixes the autocompletion for the login form.

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

98.2%

How to test

0. Activate autocompletion in your browser or make sure it is activated (see e.g. https://support.mozilla.org/en-US/kb/control-whether-firefox-automatically-fills-forms)
1. Checkout branch locally
2. Login
3. Logout
4. Go to login page again. Type the first letter of the same email address that you used for the previous login. The email address should be suggested in a dropdown.

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 an entry to CHANGELOG.md
• added 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 text in German

Aktiviere die Autovervollständigung für das Login-Formular