build: add ariaLabel to bottom sheet demo (#23601)

(cherry picked from commit aa70a34)

Author: zarend

src/dev-app/bottom-sheet/bottom-sheet-demo.ts

@@ -26,7 +26,8 @@ export class BottomSheetDemo {
     hasBackdrop: defaultConfig.hasBackdrop,
     disableClose: defaultConfig.disableClose,
     backdropClass: defaultConfig.backdropClass,
-    direction: 'ltr'
+    direction: 'ltr',
+    ariaLabel: 'Example bottom sheet'
   };
 
   @ViewChild(TemplateRef) template: TemplateRef<any>;