fix keyboardHeight

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

 
   @override
   Widget build(BuildContext context) {
-    if (editor.toolbarAction == null && _keyboardHeight != MediaQuery.of(context).viewInsets.bottom) {
+    if (MediaQuery.of(context).viewInsets.bottom > 0 && _keyboardHeight == null) {
       _keyboardHeight = MediaQuery.of(context).viewInsets.bottom;
     }
     final theme = ZefyrTheme.of(context).toolbarTheme;
     } else {
       layers.add(
         Container(
-          height: keyboardHeight,
+          height: editor.toolbarAction == null ? keyboardHeight : 0,
         ),
       );
     }