refactor(material/snack-bar): use classList.toggle

With Angular dropping IE11 support in version 13, we can now use `classList.toggle` with the second `force` param. Related to #7374

Author: jelbourn

src/material/snack-bar/snack-bar.ts

@@ -201,8 +201,7 @@ export class MatSnackBar implements OnDestroy {
     this._breakpointObserver.observe(Breakpoints.HandsetPortrait).pipe(
         takeUntil(overlayRef.detachments())
     ).subscribe(state => {
-      const classList = overlayRef.overlayElement.classList;
-      state.matches ? classList.add(this.handsetCssClass) : classList.remove(this.handsetCssClass);
+      overlayRef.overlayElement.classList.toggle(this.handsetCssClass, state.matches);
     });
 
     if (config.announcementMessage) {