fix: frontend/package.json to reduce vulnerabilities

The following vulnerabilities are fixed with an upgrade:
- https://snyk.io/vuln/SNYK-JS-ANGULARCORE-14908871

frontend/package.json

@@ -20,7 +20,7 @@
     "@angular/cdk": "19.2.18",
     "@angular/cdk-experimental": "19.2.18",
     "@angular/common": "19.2.14",
-    "@angular/core": "19.2.14",
+    "@angular/core": "19.2.18",
     "@angular/forms": "19.2.14",
     "@angular/localize": "19.2.14",
     "@angular/platform-browser": "19.2.14",