Unity builder v4 Parity Update

[AndrewKahr]

Changes

• Updated activation strategy to align with builder strategy for more stable activation with retry logic
• Added containerRegistryImageVersion and containerRegistryRepository for improved custom image support
• Added runAsHostUser to fix self-hosted runner issues
• Scripts folder cleanup
• Added error/warning annotations for activation issues
• Improved serial masking
• Image environment factory addition and docker refactoring

Related Issues

• https://github.com/game-ci/unity-test-runner/issues/245
• https://github.com/game-ci/unity-test-runner/issues/251

Related PRs

• https://github.com/game-ci/unity-test-runner/pull/231 Ended up solving the same problem in this pr
• https://github.com/game-ci/documentation/pull/442

Checklist

• [x] Read the contribution guide and accept the code of conduct
• [x] Readme (updated or not needed)
• [x] Tests (added, updated or not needed)

[github-actions[bot]]

[oasissoman]

nice!