CPLAT-7683: Finalize Component2 Tests

[kealjones-wk]

Motivation

Review tests for new UiComponent2 functionality, and ensure that there is no missing test coverage, and that all tests for UiComponent have mirrored tests for UiComponent2

AC

• react-dart
  • All tests for new lifecycle methods are already written, so we need to just review that those tests provide full coverage, and beef up coverage where need
  • Add additional tests for bridge
  • Full test coverage for JSBackedMap methods

Changes

Release Notes

Review

See CONTRIBUTING.md for more details on review types (+1 / QA +1 / +10) and code review process.

Please review:

QA Checklist

• [ ] Tests were updated and provide good coverage of the changeset and other affected code
• [ ] Manual testing was performed if needed
  • [ ] Steps from PR author:
  • [ ] Anything falling under manual testing criteria outlined in CONTRIBUTING.md

Merge Checklist

While we perform many automated checks before auto-merging, some manual checks are needed:

• [ ] A Client Platform member has reviewed these changes
• [ ] There are no unaddressed comments - this check can be automated if reviewers use the "Request Changes" feature
• [ ] For release PRs - Version metadata in Rosie comment is correct

[joebingham-wk]

Tests look good and are all passing!

QA +1