[Code] fix a tree expanding problem (#33766)

Author: spacedragon

x-pack/plugins/code/public/components/file_tree/file_tree.tsx

@@ -242,7 +242,7 @@ export class CodeFileTree extends React.Component<Props> {
   }
 
   private isPathOpen(path: string) {
-    return this.props.openedPaths.some(p => p.startsWith(path));
+    return this.props.openedPaths.includes(path);
   }
 }