title: How to put the action button when using the "snackBar.openFromComponent()" method in MatSnackBar?
body: <p>I using MatSnackBar for notifications and I would like to have an action button in the snack-bar. How do I insert one when I am using 
  <strong><em>"snackBar.openFromComponent()"</em></strong> method?</p>
  
  <p>Here is <a href="https://stackblitz.com/edit/angular-m2nc51?file=app/snack-bar-component-example.ts" rel="noreferrer">my code</a></p>