zoneless + fix signal form refresh

packages/frontend/src/app/components/new-member/new-member.component.html

@@ -1,5 +1,5 @@
 <h1>Neues Mitglied anlegen</h1>
-<form>
+<form (submit)="onSubmit(); $event.preventDefault()">
     <mat-form-field>
         <mat-label>Vorname</mat-label>
         <input matInput [field]="memberForm.vorname" />
@@ -37,7 +37,5 @@
         <mat-label>Kontakt</mat-label>
         <input matInput [field]="memberForm.kontakt" />
     </mat-form-field>
-    <button mat-flat-button color="primary" (click)="onSubmit()">
-        Hinzufügen
-    </button>
+    <button mat-flat-button color="primary" type="submit">Hinzufügen</button>
 </form>