build(deps): bump @ng-select/ng-select in /frontend

Bumps [@ng-select/ng-select](https://github.com/ng-select/ng-select) from 13.7.0 to 13.7.1.
- [Release notes](https://github.com/ng-select/ng-select/releases)
- [Changelog](https://github.com/ng-select/ng-select/blob/master/CHANGELOG.md)
- [Commits](ng-select/ng-select@v13.7.0...v13.7.1)

---
updated-dependencies:
- dependency-name: "@ng-select/ng-select"
  dependency-type: direct:production
  update-type: version-update:semver-patch
...

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