fix: propagate menu-bar item tooltip to connector items (#9216)

## Description

The new `MenuBarTooltipController` in `@vaadin/menu-bar` 25.2.0-alpha9
(introduced in
[vaadin/web-components#11586](vaadin/web-components#11586))
short-circuits in `setTarget` when the target's item has no `tooltip`
property — it clears the target and closes the tooltip immediately.
Flow's connector built items without a `tooltip` field (tooltip text was
only stored on the wrapper component and read via a custom generator),
so menu-bar tooltips never opened.

Fix: copy `tooltip` from the wrapper component onto each item in
`menubarConnector.js` so the controller's gating check recognizes the
item as having a tooltip. The existing custom generator continues to
read the live value from `item.component.tooltip`, so updates via
`setTooltipText` still display the latest text.

Verified `MenuBarTooltipIT` passes (3/3) against local `web-components`
at `main`.

## Type of change

- Bugfix

---------

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: vursen

vaadin-menu-bar-flow-parent/vaadin-menu-bar-flow/src/main/java/com/vaadin/flow/component/menubar/MenuBar.java

@@ -500,19 +500,11 @@ public MenuBarI18n setMoreOptions(String moreOptions) {
     public void setTooltipText(MenuItem item, String tooltipText) {
         if (!getElement().getChildren().anyMatch(
                 child -> "tooltip".equals(child.getAttribute("slot")))) {
-            // No <vaadin-tooltip> yet added, add one
-            Element tooltipElement = new Element("vaadin-tooltip");
-
-            tooltipElement.addAttachListener(e -> {
-                // Assigns a generator that reads the tooltip property of the
-                // item component
-                tooltipElement.executeJs(
-                        "this.generator = ({item}) => { return (item && item.component) ? item.component.tooltip : ''; }");
-            });
-            SlotUtils.addToSlot(this, "tooltip", tooltipElement);
+            SlotUtils.addToSlot(this, "tooltip", new Element("vaadin-tooltip"));
         }
 
         item.getElement().setProperty("tooltip", tooltipText);
+        updateButtons();
     }
 
     /**

vaadin-menu-bar-flow-parent/vaadin-menu-bar-flow/src/main/resources/META-INF/resources/frontend/menubarConnector.js

@@ -72,6 +72,10 @@ function initLazy(menubar, appId) {
         // Propagate disabled state from items to parent buttons
         item.disabled = item.component.disabled;
 
+        // Propagate tooltip text so the menu-bar's tooltip controller
+        // recognizes the item as having a tooltip and shows it.
+        item.tooltip = item.component.tooltip;
+
         // Saving item to component because `_item` can be reassigned to a new value
         // when the component goes to the overflow menu
         item.component._rootItem = item;