Don't wrap the QuillEditor's child in the EditorTextSelectionGestureDetector if selection is disabled (#890)

lib/src/widgets/editor.dart

@@ -498,11 +498,14 @@ class QuillEditorState extends State<QuillEditor>
     );
 
     final editor = I18n(
-        initialLocale: widget.locale,
-        child: _selectionGestureDetectorBuilder.build(
-          behavior: HitTestBehavior.translucent,
-          child: child,
-        ));
+      initialLocale: widget.locale,
+      child: selectionEnabled
+          ? _selectionGestureDetectorBuilder.build(
+              behavior: HitTestBehavior.translucent,
+              child: child,
+            )
+          : child,
+    );
 
     if (kIsWeb) {
       // Intercept RawKeyEvent on Web to prevent it from propagating to parents