title: angular material stepper: disable header navigation
body: <p>I want to navigate the stepper only through the next and back buttons. </p>
  
  <p>I can't get this to work since users can also click each step label to navigate to any step. I can't use linear, since it requires each step to have a <code>formArray</code> or <code>FormGroup</code>.</p>
  
  <p>I have tried <code>&lt;mat-step (click)="$event.stopPropagation()"&gt;</code>.</p>