fix _keyboardHeight

packages/zefyr/lib/src/widgets/toolbar.dart

 
   @override
   Widget build(BuildContext context) {
-    _keyboardHeight = MediaQuery.of(context).viewInsets.bottom;
+    if (editor.toolbarAction == null) {
+      _keyboardHeight = MediaQuery.of(context).viewInsets.bottom;
+    }
     final theme = ZefyrTheme.of(context).toolbarTheme;
 
     final kToolbarDivider = Container(