build(deps): bump @fullcalendar/angular

Bumps the fullcalendar group in /frontend with 1 update: [@fullcalendar/angular](https://github.com/fullcalendar/fullcalendar-angular).


Updates `@fullcalendar/angular` from 6.1.15 to 6.1.16
- [Release notes](https://github.com/fullcalendar/fullcalendar-angular/releases)
- [Changelog](https://github.com/fullcalendar/fullcalendar-angular/blob/main/CHANGELOG.md)
- [Commits](fullcalendar/fullcalendar-angular@v6.1.15...v6.1.16)

---
updated-dependencies:
- dependency-name: "@fullcalendar/angular"
  dependency-type: direct:production
  update-type: version-update:semver-patch
  dependency-group: fullcalendar
...

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