title: Angular Material - Prevent mat-stepper from navigating between steps
body: <p>I have a <code>mat-horizontal-stepper</code> where I set linear property as true. When all the steps are valid as of now I can navigate to previous steps by clicking the header or label. I don't want that property. </p>
  
  <p>I need to navigate only through buttons. </p>
  
  <p>I tried disabling pointer function with: </p>
  
  <pre><code>    .mat-horizontal-stepper-header{
         pointer-events: none;
       }
  </code></pre>
  
  <p>but it didn't worked. </p>
  
  <p>I need either to stop navigating by clicking header or fire a function on clicking the stepper header.</p>