Bump chart.js from 2.7.2 to 2.9.4 in /src/Frontend/camFrontend

Bumps [chart.js](https://github.com/chartjs/Chart.js) from 2.7.2 to 2.9.4.
- [Release notes](https://github.com/chartjs/Chart.js/releases)
- [Commits](chartjs/Chart.js@v2.7.2...v2.9.4)

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

src/Frontend/camFrontend/package.json

@@ -25,7 +25,7 @@
     "@angular/router": "^6.0.3",
     "@nicky-lenaers/ngx-scroll-to": "^1.0.0",
     "bootstrap": "^4.5.2",
-    "chart.js": "^2.7.2",
+    "chart.js": "^2.9.4",
     "core-js": "^2.5.4",
     "elasticsearch": "^15.4.1",
     "hammerjs": "^2.0.8",