[Catalog][BottomAppBar] remove the overflow menu from the bottom app bar demo

PiperOrigin-RevId: 431749183

Author: veganafro

catalog/java/io/material/catalog/bottomappbar/res/menu/demo_primary_alternate.xml

@@ -28,5 +28,5 @@
   <item
     android:icon="@drawable/ic_dashboard_24px"
     android:title="@string/cat_bottomappbar_dashboard"
-    app:showAsAction="never"/>
+    app:showAsAction="ifRoom"/>
 </menu>