No error message for Schedule Error

When saving invalid schedule, error is returned from API, but not displayed. Simple way to recreate is schedule item and enter invalid year (I.E. 0000). 

I think this may be proper fix, other solution is to remove the catcherror and extra pipe.

src/Squidex/app/shared/state/contents.state.ts

@@ -12,6 +12,7 @@ import { catchError, distinctUntilChanged, map, switchMap, tap } from 'rxjs/oper
 import {
     DateTime,
     DialogService,
+    ErrorDto,
     ImmutableArray,
     notify,
     Pager,
@@ -152,7 +153,7 @@ export abstract class ContentsStateBase extends State<Snapshot> {
                 this.contentsService.changeContentStatus(this.appName, this.schemaName, c.id, action, dueTime, c.version).pipe(
                     catchError(error => of(error))))).pipe(
             tap(results => {
-                const error = results.find(x => !!x.error);
+                const error = results.find(x => x instanceof ErrorDto);
 
                 if (error) {
                     this.dialogs.notifyError(error);
@@ -169,7 +170,7 @@ export abstract class ContentsStateBase extends State<Snapshot> {
                 this.contentsService.deleteContent(this.appName, this.schemaName, c.id, c.version).pipe(
                     catchError(error => of(error))))).pipe(
             tap(results => {
-                const error = results.find(x => !!x.error);
+                const error = results.find(x => x instanceof ErrorDto);
 
                 if (error) {
                     this.dialogs.notifyError(error);
@@ -389,4 +390,4 @@ const discardChanges = (content: ContentDto, user: string, version: Version, now
         lastModified: now || DateTime.now(),
         lastModifiedBy: user,
         version
-    });
+    });