Catch errors in form update

frontend/app/components/api/api-v3/hal-resources/work-package-resource.service.ts

@@ -97,8 +97,7 @@ export class WorkPackageResource extends HalResource {
 
   public getForm() {
     if (!this.form) {
-      this.form = this.$links.update(this);
+      this.updateForm(this.$source).catch(error => {
-      this.form.catch(error => {
         NotificationsService.addError(error.data.message);
       });
     }
@@ -163,7 +162,8 @@ export class WorkPackageResource extends HalResource {
           }).catch((error) => {
           deferred.reject(error);
         });
-      });
+      })
+      .catch(deferred.reject);
 
     return deferred.promise;
   }