Revert "update focus_mangaer"

This reverts commit 243b3b1ba5165364d1cd363a8130203c9028d7e6.

com.unity.uiwidgets/Runtime/widgets/focus_manager.cs

 
         public FocusAttachment _attachment;
 
-
+<<<<<<< HEAD
+=======
+        IEnumerable<FocusNode> descendants {
+>>>>>>> parent of a10f14fb... Merge branch 'dev_1.17.5' into shiyun/skia
             get {
                 if (_descendants == null) {
                     List<FocusNode> result = new List<FocusNode>();