[flutter]: force the editor as large as parent

app_flowy/lib/workspace/presentation/stack_page/doc/doc_page.dart

@@ -91,7 +91,7 @@ class _DocPageState extends State<DocPage> {
         axis: Axis.vertical,
         controller: scrollController,
         barSize: 6.0,
-        child: Padding(padding: EdgeInsets.zero, child: editor),
+        child: SizedBox.expand(child: editor),
       ),
     );
   }