Immediately fetch initial chat data in adapter (+fix customDataModel flakey UI test) (#1168)

Author: JamesBurnside

change/@internal-react-composites-b180611a-ab99-4ff8-83ac-2a71c26ec1b7.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "Immediately fetch initial chat data when creating azure communication chat adapter",
+  "packageName": "@internal/react-composites",
+  "email": "2684369+JamesBurnside@users.noreply.github.com",
+  "dependentChangeType": "patch"
+}

packages/react-composites/src/composites/ChatComposite/adapter/AzureCommunicationChatAdapter.ts

@@ -356,10 +356,11 @@ export const createAzureCommunicationChatAdapter = async ({
     credential: credential
   });
   const chatThreadClient = await chatClient.getChatThreadClient(threadId);
+  await chatClient.startRealtimeNotifications();
 
-  chatClient.startRealtimeNotifications();
+  const adapter = await createAzureCommunicationChatAdapterFromClient(chatClient, chatThreadClient);
+  await adapter.fetchInitialData();
 
-  const adapter = createAzureCommunicationChatAdapterFromClient(chatClient, chatThreadClient);
   return adapter;
 };