Bump requestretry and karma in /ui

Bumps [requestretry](https://github.com/FGRibreau/node-request-retry) and [karma](https://github.com/karma-runner/karma). These dependencies needed to be updated together.

Removes `requestretry`

Updates `karma` from 2.0.5 to 6.4.0
- [Release notes](https://github.com/karma-runner/karma/releases)
- [Changelog](https://github.com/karma-runner/karma/blob/master/CHANGELOG.md)
- [Commits](karma-runner/karma@v2.0.5...v6.4.0)

---
updated-dependencies:
- dependency-name: requestretry
  dependency-type: indirect
- dependency-name: karma
  dependency-type: direct:development
...

Signed-off-by: dependabot[bot] <[email protected]>