fix(ivy): DebugElement.triggerEventHandler not picking up events registered via Renderer2 (#31845)

Fixes Ivy's `DebugElement.triggerEventHandler` to picking up events that have been registered through a `Renderer2`, unlike ViewEngine.

This PR resolves FW-1480.

PR Close #31845

packages/platform-browser/src/dom/dom_renderer.ts

@@ -49,12 +49,20 @@ export function flattenStyles(
 
 function decoratePreventDefault(eventHandler: Function): Function {
   return (event: any) => {
+    // Ivy uses `Function` as a special token that allows us to unwrap the function
+    // so that it can be invoked programmatically by `DebugNode.triggerEventHandler`.
+    if (event === Function) {
+      return eventHandler;
+    }
+
     const allowDefaultBehavior = eventHandler(event);
     if (allowDefaultBehavior === false) {
       // TODO(tbosch): move preventDefault into event plugins...
       event.preventDefault();
       event.returnValue = false;
     }
+
+    return undefined;
   };
 }