Directly initialize JwtHelperService in auth service

frontend/src/app/services/auth.service.ts

@@ -15,11 +15,11 @@ export class AuthService {
 
   private userClaimsSubject = new BehaviorSubject<JwtClaims | null>(null);
   public userClaims$ = this.userClaimsSubject.asObservable();
+  private jwtHelper = new JwtHelperService();
 
   constructor(
     private loginService: LoginService,
-    private snackBar: MatSnackBar,
-    private jwtHelper: JwtHelperService
+    private snackBar: MatSnackBar
   ) {
     // Check if user is already logged in on service initialization
     this.checkAuthStatus();