Unhover on mouse exit of tree

Summary: This was causing the hover state to linger which is now quite noticable in the tree

Reviewed By: lblasa

Differential Revision: D41548249

fbshipit-source-id: cdf8ed434aa064dba05ebf31773bedaef18ba007

desktop/plugins/public/ui-debugger/components/Tree.tsx

@@ -58,6 +58,10 @@ export function Tree(props: {
   }, [props.selectedNode]);
 
   return (
+    <div
+      onMouseLeave={() => {
+        instance.uiState.hoveredNodes.set([]);
+      }}>
       <HighlightProvider
         text={searchTerm}
         highlightColor={theme.searchHighlightBackground.yellow}>
@@ -122,6 +126,7 @@ export function Tree(props: {
           />
         </ControlledTreeEnvironment>
       </HighlightProvider>
+    </div>
   );
 }