Fix typo in comment from 'childs' to 'children'

Author: AbdeMohlbi

engine/src/flutter/shell/platform/android/io/flutter/plugin/platform/SingleViewPresentation.java

@@ -74,7 +74,7 @@ static class PresentationState {
   // so when we create the platform view we can tell it its view id.
   private int viewId;
 
-  // The root view for the presentation, it has 2 childs: container which contains the embedded
+  // The root view for the presentation, it has 2 children: container which contains the embedded
   // view, and
   // fakeWindowViewGroup which contains views that were added directly to the presentation's window
   // manager.