Focus and keyboard navigation do not work in search results when disabled parents

从 issue 中描述的入口点 getFirstMatchingNode 开始，使用链接的 CodeSandbox 重现该行为，并比较父元素被禁用和父元素启用的情况。验证匹配的已启用子元素可以获得焦点并使用 Enter 进行选择，然后在 repository 中存在相关测试时，添加或更新回归测试覆盖。

What is expected?

When the tree select search is used, focus is given to the first element, users can press 'Enter' to select it or use 'up' and 'down' keys to navigate other search results

Disabled elements in the search should not be given focus, but if their children are enabled their children should still be focused in search results

What is actually happening?

Any element with a disabled parent somewhere in their hierarchy is not given focus when searching, 'Enter' key will select the first element in the tree instead

This is bad UX but also not good for accessibility

I am using master from this repo during testing

Steps to reproduce
I have a demo sandbox here made with AntD but exact behaviour comes from rc-tree-select, I can adjust the demo if needed: https://codesandbox.io/p/devbox/confident-resonance-8jv7cz

The demo shows two cases, one working (No disabled parents) and one broken (Disabled parent)

To show the component not working:

Click on the treeselect search
Search for '1' (Or '2', or '3')
The child element gets focus, pressing enter on keyboard does nothing

To show the component working as expected:

Click on the treeselect search
Search for '3' (Or '4', or '5')
The child element gets focus, pressing enter on keyboard selects element

Suggested code fix - even if a parent is disabled or not selectable, check children

// ========================== Get First Selectable Node ==========================
const getFirstMatchingNode = (nodes: EventDataNode<any>[]): EventDataNode<any> | null => {
  for (const node of nodes) {
-    if (node.disabled || node.selectable === false) {
-      continue;
-    }
-
-    if (searchValue) {
-      if (filterTreeNode(node)) {
-        return node;
-      }
-    } else {
-      return node;
-    }
+    const isNodeSelectable = !node.disabled && node.selectable !== false;
+
+    if (isNodeSelectable) {
+      if (searchValue) {
+        if (filterTreeNode(node)) {
+          return node;
+        }
+      } else {
+        return node;
+      }
+    }
 
     if (node[fieldNames.children]) {
       const matchInChildren = getFirstMatchingNode(node[fieldNames.children]);
       if (matchInChildren) {
         return matchInChildren;
       }
     }
   }
   return null;
};

Demo before;

Demo after;

Initially created as an antD issue

Please let me know if I can provide any more information