LibWeb: Make factory methods of IDLEventListener and NodeFilter fallible

Author: https://github.com/kennethmyhra
Commit: 1f48081ee4
Pull-request: https://github.com/SerenityOS/serenity/pull/17542

Userland/Libraries/LibWeb/DOM/EventTarget.cpp

@@ -561,7 +561,7 @@ void EventTarget::activate_event_handler(DeprecatedFlyString const& name, HTML::
     // 5. Let listener be a new event listener whose type is the event handler event type corresponding to eventHandler and callback is callback.
     auto listener = realm.heap().allocate_without_realm<DOMEventListener>();
     listener->type = name;
-    listener->callback = IDLEventListener::create(realm, *callback).ptr();
+    listener->callback = IDLEventListener::create(realm, *callback).release_value_but_fixme_should_propagate_errors();
 
     // 6. Add an event listener with eventTarget and listener.
     add_an_event_listener(*listener);