Ensure editor is focused before calling insert HTML

enough_html_editor uses execCommand to insert HTML. However
execCommand only works if the contenteditable element is focused. So
inserting or replacing Scribe result do not work if the user did not
click before in the composer.

Here we manually focus the contenteditable element to fix this before
inserting content.

lib/features/composer/presentation/controller/rich_text_mobile_tablet_controller.dart

@@ -19,6 +19,14 @@ class RichTextMobileTabletController extends GetxController {
 
   Future<bool> get isEditorFocused async => await htmlEditorApi?.hasFocus() ?? false;
 
+  Future<void> focus() async {
+    try {
+      await htmlEditorApi?.webViewController.evaluateJavascript(source: "document.getElementById('editor').focus();");
+    } catch (e) {
+      logWarning('RichTextMobileTabletController::focus:Exception: $e');
+    }
+  }
+
   void insertImage(InlineImage inlineImage) async {
     final isFocused = await isEditorFocused;
     log('RichTextMobileTabletController::insertImage: isEditorFocused = $isFocused');