fixed snackbar dialogue

src/app/helper/snackbar-dialog.html

@@ -2,5 +2,5 @@
 
 <div mat-dialog-content *ngFor="let error of errorMessages">{{error["message"]}}</div>
 <div mat-dialog-actions>
-  <button mat-button mat-dialog-close>Close</button>
+  <button mat-button mat-dialog-close>Schließen</button>
 </div>