test: fix app_links test

Author: Vinzent03

packages/supabase_flutter/test/supabase_flutter_test.dart

@@ -145,7 +145,8 @@ void main() {
       // Wait for the initial app link to be handled, as this is an async
       // process when mocking the event channel.
       if (mockEventChannel) {
-        await AppLinks().uriLinkStream.first;
+        await AppLinks().getLatestLink();
+        await Future.delayed(const Duration(milliseconds: 500));
       }
       expect(pkceHttpClient.requestCount, 1);
       expect(pkceHttpClient.lastRequestBody['auth_code'], 'my-code-verifier');