Fix #943 by not resetting whitespace to bad values (for Firefox)

What does this MR do?

Fix #943 (closed) by not resetting whitespace to bad values (for Firefox)

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

Honestly, I'm confident it has more "risk" of making things better than making them worse :)

Links to related issues

• apparently committed (not intentionally) as part of 422d850e
• Reported in #943 (closed)
• Slack https://yunity.slack.com/archives/C74JC2V26/p1594907015046100
• Slack https://yunity.slack.com/archives/C1T1ZM9A4/p1594571215233800

How to test

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

1. Use Firefox
2. Try writing a new forum post with newlines as described in #943 (closed)
3. Try writing a new forum reply with newlines as described in #943 (closed)

Checklist

• added a test, or explain why one is not needed/possible...
• no unrelated changes
• asked someone for a code review
• added an entry to CHANGELOG.md (description, merge request link, username(s))
• 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.