Fleet UI: Fleet maintained app 404 sends to 404 page

[RachelElysia]

Issue

For #24638

Description

• Fleet maintained app 404 sends to 404 page
• Remove 3 retries to match other pages that send to 404 immediately after first try (e.g. host details page 404)

If some of the following don't apply, delete the relevant line.

• Manual QA for all new/changed functionality

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 63.83%. Comparing base (efe3315) to head (bf5d10d).
Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #25167   +/-   ##
=======================================
  Coverage   63.83%   63.83%           
=======================================
  Files        1615     1615           
  Lines      153602   153602           
  Branches     3986     3986           
=======================================
  Hits        98046    98046           
  Misses      47754    47754           
  Partials     7802     7802           

Flag	Coverage Δ
frontend	53.26% <ø> (ø)

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