fix: break out stopping... states from stopped states in webui

[ashtonG]

Description

This fixes an issue where experiments that were stopping for one reason or another showed as stopped.

Test Plan

submit an experiment
on the experiment's detail page, cancel the experiment
the experiment state should show up as stopping before updating to stopped.

Checklist

• Changes have been manually QA'd
• User-facing API changes need the "User-facing API Change" label.
• Release notes should be added as a separate file under docs/release-notes/.
  See Release Note for details.
• Licenses should be included for new code which was copied and/or modified from any external code.

Ticket

WEB-1913

[netlify]

✅ Deploy Preview for determined-ui canceled.

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🔨 Latest commit	d19433b
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[codecov]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (9dc4fc8) 51.46% compared to head (d19433b) 47.27%.
Report is 11 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #8672      +/-   ##
==========================================
- Coverage   51.46%   47.27%   -4.19%     
==========================================
  Files         882      569     -313     
  Lines      156047   117643   -38404     
  Branches     2084     2088       +4     
==========================================
- Hits        80302    55613   -24689     
+ Misses      74255    60540   -13715     
  Partials     1490     1490              

Flag	Coverage Δ
harness	?
web	53.77% <83.33%> (+<0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files	Coverage Δ
webui/react/src/components/ExperimentIcons.tsx	86.66% <83.33%> (-0.61%)	⬇️

... and 313 files with indirect coverage changes

[EmilyBonar]

LGTM!