Fleet UI: UX Cleanups to match new patterns

[RachelElysia]

Issue

Closes #33713

Description

I told myself I'd stop working on this when I stopped noticing things, sorry!

These are in a larger, not broken down PR as I don't think these are release blocking, but they are definitely nice to haves and at the very least should go in the next release, 4.76.0.

Details/screenshots

More details/screenshots in my working hours tomorrow

• QA'd all new/changed functionality manually

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 64.00%. Comparing base (9833214) to head (8bc12fc).
⚠️ Report is 8 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main   #33730      +/-   ##
==========================================
- Coverage   64.00%   64.00%   -0.01%     
==========================================
  Files        2068     2068              
  Lines      207234   207235       +1     
  Branches     6822     6730      -92     
==========================================
  Hits       132646   132646              
- Misses      64157    64158       +1     
  Partials    10431    10431              

Flag	Coverage Δ
frontend	53.34% <100.00%> (-0.01%)	⬇️

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[lukeheath]

Loosk good!