Bump chart.js from 2.9.3 to 2.9.4

Bumps [chart.js](https://github.com/chartjs/Chart.js) from 2.9.3 to 2.9.4.
- [Release notes](https://github.com/chartjs/Chart.js/releases)
- [Commits](chartjs/Chart.js@v2.9.3...v2.9.4)

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

package.json

@@ -28,7 +28,7 @@
     "angular-bootstrap-md": "^9.3.1",
     "animate.css": "^4.1.0",
     "bootstrap": "^4.5.0",
-    "chart.js": "^2.9.3",
+    "chart.js": "^2.9.4",
     "firebase": "^7.15.1",
     "hammerjs": "^2.0.8",
     "jquery": "^3.5.1",