fix: Trigger app post user created event correctly (#30006)

.changeset/slow-lizards-breathe.md

+---
+'@rocket.chat/meteor': patch
+---
+
+Fixed Apps-Engine event `IPostUserCreated` execution

apps/meteor/app/authentication/server/startup/index.js

@@ -249,11 +249,6 @@ const onCreateUserAsync = async function (options, user = {}) {
 		await callbacks.run('onCreateUser', options, user);
 	}
 
-	if (!options.skipAppsEngineEvent) {
-		// App IPostUserCreated event hook
-		await Apps.triggerEvent(AppEvents.IPostUserCreated, { user, performedBy: await safeGetMeteorUser() });
-	}
-
 	if (!options.skipEmailValidation && !validateEmailDomain(user)) {
 		throw new Meteor.Error(403, 'User validation failed');
 	}
@@ -353,6 +348,13 @@ const insertUserDocAsync = async function (options, user) {
 		}
 	}
 
+	if (!options.skipAppsEngineEvent) {
+		// `post` triggered events don't need to wait for the promise to resolve
+		Apps.triggerEvent(AppEvents.IPostUserCreated, { user, performedBy: await safeGetMeteorUser() }).catch((e) => {
+			Apps.getRocketChatLogger().error('Error while executing post user created event:', e);
+		});
+	}
+
 	return _id;
 };