codemirror: Properly handle line breaks in singleline mode
Created by: fkling
Camden discovered that pasting a search query containing a line break isn't possible because we simply ignore all transactions that contain a line break (which results in ignore the pasted content).
With this change we are now removing/replacing line breaks instead.
Test plan
Manually tested. I'll add an integration tests once #36044 is merged.
https://user-images.githubusercontent.com/179026/172418019-911938d3-c458-4265-8353-9942b21e8b15.mp4
App preview:
Check out the client app preview documentation to learn more.
