Follow-up: Improve UX of audit events streams UI

The following discussion from !91692 (merged) should be addressed:

• @annabeldunstone started a discussion: (+2 comments)

  UX Suggestions (nit-picks, not urgent)

  1. Can we align these two tables?

  

  2. These (header, value) could probably be full-width inputs on mobile:

  

  3. Could we use text here instead of (or in addition to) this ambiguous icon? Something like 3 active streams or something. I think the button could also be changed to Add stream but that's just an opinion.