LibWeb: Make factory methods of HTML::MessageEvent fallible

Author: https://github.com/kennethmyhra
Commit: 7ec444047c
Pull-request: https://github.com/SerenityOS/serenity/pull/17491
Reviewed-by: https://github.com/linusg ✅

Userland/Libraries/LibWeb/HTML/MessagePort.cpp

@@ -99,7 +99,7 @@ void MessagePort::post_message(JS::Value message)
         MessageEventInit event_init {};
         event_init.data = message;
         event_init.origin = "<origin>";
-        target_port->dispatch_event(*MessageEvent::create(target_port->realm(), HTML::EventNames::message, event_init));
+        target_port->dispatch_event(MessageEvent::create(target_port->realm(), HTML::EventNames::message, event_init).release_value_but_fixme_should_propagate_errors());
     }));
 }