feat(material-experimental/selection): selection column row check box should prevent click event propagation

[andrewalderson]

Feature Description

In the template for MatSelectionColumn the checkbox for each row should not propagate the click event up to the row.

Use Case

When you have a table that uses the entire row as a click zone the event from this checkbox is causing the row click event to be fired.

This is from the current documentation for adding selection to the MatTable

<ng-container matColumnDef="select">
  <th mat-header-cell *matHeaderCellDef>
    <mat-checkbox (change)="$event ? masterToggle() : null"
                  [checked]="selection.hasValue() && isAllSelected()"
                  [indeterminate]="selection.hasValue() && !isAllSelected()">
    </mat-checkbox>
  </th>
  <td mat-cell *matCellDef="let row">
    <mat-checkbox (click)="$event.stopPropagation()"
                  (change)="$event ? selection.toggle(row) : null"
                  [checked]="selection.isSelected(row)">
    </mat-checkbox>
  </td>
</ng-container>

The checkbox for the row prevents the click event from propagating. The template for the new SelectionColumn should do the same thing.