Added enhanced validation for raw labels

[bsekachev]

Motivation and context

To prevent incorrect configuration passed to the server.
It would be nice to implement similar checks on server level, however this patch is only to enhance UI.

How has this been tested?

Checklist

• I submit my changes into the develop branch
• I have created a changelog fragment
• I have updated the documentation accordingly
• I have added tests to cover my changes
• I have linked related issues (see GitHub docs)

License

• I submit my code changes under the same MIT License that covers the project.
  Feel free to contact the maintainers if that's a concern.

[sonarqubecloud]

Quality Gate passed

Issues
2 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[codecov-commenter]

Codecov Report

❌ Patch coverage is 50.98039% with 25 lines in your changes missing coverage. Please review.
✅ Project coverage is 73.72%. Comparing base (f2241f9) to head (e38351c).

Additional details and impacted files

@@             Coverage Diff             @@
##           develop    #9677      +/-   ##
===========================================
- Coverage    74.36%   73.72%   -0.64%     
===========================================
  Files          455      400      -55     
  Lines        47359    44422    -2937     
  Branches      3963     3974      +11     
===========================================
- Hits         35217    32751    -2466     
+ Misses       12142    11671     -471     

Components	Coverage Δ
cvat-ui	77.62% <50.98%> (-0.08%)	⬇️
cvat-server	70.37% <ø> (-1.44%)	⬇️

🚀 New features to boost your workflow:

• ❄️ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.
• 📦 JS Bundle Analysis: Save yourself from yourself by tracking and limiting bundle sizes in JS merges.