fix: replace unsupported _vue selector with getByLabel in VueNodeHelpers

Amp-Thread-ID: https://ampcode.com/threads/T-019c169e-9615-7608-9421-0c009920efe4
Co-authored-by: Amp <amp@ampcode.com>

browser_tests/fixtures/VueNodeHelpers.ts

@@ -148,9 +148,9 @@ export class VueNodeHelpers {
    * Get a specific widget by node title and widget name
    */
   getWidgetByName(nodeTitle: string, widgetName: string): Locator {
-    return this.getNodeByTitle(nodeTitle).locator(
-      `_vue=[widget.name="${widgetName}"]`
-    )
+    return this.getNodeByTitle(nodeTitle).getByLabel(widgetName, {
+      exact: true
+    })
   }
 
   /**