Bump ng2-charts from 5.0.4 to 6.0.0 in /frontend/src/main/webapp

Bumps [ng2-charts](https://github.com/valor-software/ng2-charts) from 5.0.4 to 6.0.0.
- [Release notes](https://github.com/valor-software/ng2-charts/releases)
- [Commits](valor-software/ng2-charts@v5.0.4...v6.0.0)

---
updated-dependencies:
- dependency-name: ng2-charts
  dependency-type: direct:production
  update-type: version-update:semver-major
...

Signed-off-by: dependabot[bot] <support@github.com>

frontend/src/main/webapp/package.json

@@ -53,7 +53,7 @@
     "moment": "2.30.1",
     "nanoid": "5.0.6",
     "ng": "0.0.0",
-    "ng2-charts": "5.0.4",
+    "ng2-charts": "6.0.0",
     "ngx-cookie-service": "17.1.0",
     "ngx-scrollbar": "13.0.3",
     "rxjs": "7.8.1",