Fix AI Scribe overlay button display in iOS

The button was never displayed because the selectionchange event listener was loaded when the WebView was not entirely loaded so selectionchange event were never fired.

Now we setup selection listener when the WebView is loaded instead of created.

lib/features/composer/presentation/widgets/mobile/mobile_editor_widget.dart

@@ -89,6 +89,10 @@ class _MobileEditorState extends State<MobileEditorWidget> with TextSelectionMix
 
   Future<void> _onWebViewCreated(HtmlEditorApi editorApi) async {
     widget.onCreatedEditorAction.call(context, editorApi, widget.content);
+  }
+
+  Future<void> _onWebViewCompleted(HtmlEditorApi editorApi, WebUri? webUri) async {
+    widget.onLoadCompletedEditorAction(editorApi, webUri);
     try {
       await _setupSelectionListener(editorApi);
     } catch (e) {
@@ -96,6 +100,7 @@ class _MobileEditorState extends State<MobileEditorWidget> with TextSelectionMix
     }
   }
 
+
   @override
   Widget build(BuildContext context) {
     return HtmlEditor(
@@ -109,7 +114,7 @@ class _MobileEditorState extends State<MobileEditorWidget> with TextSelectionMix
         useDefaultFontStyle: true,
       ),
       onCreated: _onWebViewCreated,
-      onCompleted: widget.onLoadCompletedEditorAction,
+      onCompleted: _onWebViewCompleted,
       onContentHeightChanged: PlatformInfo.isIOS ? widget.onEditorContentHeightChanged : null,
     );
   }