Validation fixes for color theming in plot selection list

[IanMatthewHuff]

Validation fixes for follow up to:
#8212

• Pull request represents a single change (i.e. not fixing disparate/unrelated things in a single PR)
• Title summarizes what is changing
• Has a news entry file (remember to thank yourself!)
• Appropriate comments and documentation strings in the code
• Has sufficient logging.
• Has telemetry for enhancements.
• Unit tests & system/integration tests are added/updated
• Test plan is updated as appropriate
• package-lock.json has been regenerated by running npm install (if dependencies have changed)
• The wiki is updated with any design decisions/details.

[codecov-io]

Codecov Report

Merging #8224 into master will increase coverage by 0.35%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #8224      +/-   ##
==========================================
+ Coverage   58.32%   58.67%   +0.35%     
==========================================
  Files         504      504              
  Lines       22740    23107     +367     
  Branches     3725     3725              
==========================================
+ Hits        13262    13558     +296     
- Misses       8601     8672      +71     
  Partials      877      877

Impacted Files	Coverage Δ
src/client/testing/serviceRegistry.ts	48.64% <0%> (-44.21%)	⬇️
...t/datascience/jupyter/jupyterDataRateLimitError.ts	66.66% <0%> (-33.34%)	⬇️
src/client/formatters/serviceRegistry.ts	75% <0%> (-25%)	⬇️
...ience/jupyter/jupyterDebuggerRemoteNotSupported.ts	75% <0%> (-25%)	⬇️
src/client/common/utils/icons.ts	83.33% <0%> (-16.67%)	⬇️
src/client/testing/codeLenses/main.ts	44.44% <0%> (-15.56%)	⬇️
src/client/api.ts	78.57% <0%> (-11.43%)	⬇️
src/client/common/utils/version.ts	77.77% <0%> (-1.39%)	⬇️
src/client/providers/providerUtilities.ts	83.33% <0%> (-1.29%)	⬇️
...lient/datascience/jupyter/jupyterSelfCertsError.ts	100% <0%> (ø)	⬆️
... and 27 more

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