Fix editor to start at top of screen

lib/screens/editor.dart

@@ -100,7 +100,7 @@ class _EditorScreenState extends State<EditorScreen> {
 
     final mainBody = Padding(
       padding: const EdgeInsets.all(8.0),
-      child: Center(
+      child: Container(
         child: SingleChildScrollView(
           child: Column(
             crossAxisAlignment: CrossAxisAlignment.start,