feat: add class color in getClasses return value

[haakonflatval-cognite]

Type of change

Jira ticket 📘

https://cognitedata.atlassian.net/browse/

Description 📝

Add color in getClasses return value for point clouds

How has this been tested? 🔍

It hasn't

Test instructions ℹ️

Checklist ☑️

• I am proud of this feature.
• I have performed a self-review of my own code.
• I have added PR type (Feat, Bug, Chore, Test, Docs, Style, Refactor) to the PR title.
• I have manually tested this for different scenarios (different models, formats, devices, browsers).
• I have commented my code in hard-to-understand areas.
• I have made corresponding changes to the public documentation.
• I have added unit and visuals tests to prove that my feature works to the best of my ability.
• I have refactored the code for readability to the best of my ability.
• I have checked that my changes do not introduce regressions in the public documentation.
• I have outlined any known defects / lacking capabilities in the contents of this PR.
• I have listed any remaining work that should follow this PR in the description or jira/miro/etc.
• I have added TSDoc to any public facing changes.
• I have added "developer documentation" in any package README.md that is related / applicable to this PR.
• I have noted down and am currently tracking any technical debt introduced in this PR.
• I have thoroughly thought about the architecture of this implementation.
• I have asked peers to test this feature.

[codecov]

Codecov Report

Merging #3885 (bf76ff8) into master (1d22ee1) will increase coverage by 0.00%.
Report is 7 commits behind head on master.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #3885   +/-   ##
=======================================
  Coverage   71.42%   71.42%           
=======================================
  Files         351      351           
  Lines       35102    35103    +1     
  Branches     2678     2677    -1     
=======================================
+ Hits        25073    25074    +1     
  Misses       9921     9921           
  Partials      108      108           

Files	Coverage Δ
.../packages/pointclouds/src/ClassificationHandler.ts	89.36% <100.00%> (+0.07%)	⬆️
...packages/pointclouds/src/CognitePointCloudModel.ts	85.90% <100.00%> (ø)
viewer/packages/pointclouds/src/PointCloudNode.ts	75.00% <100.00%> (ø)

[christjt]

LGTM!