in_app_purchase iOS native plugin tests are flaky

[jmagman]

"testDiscountedProductSuccess()" in RunnerTests failed with:
Asynchronous wait failed: Exceeded timeout of 5 seconds, with unfulfilled expectations: "Purchase request should succeed".

"testDiscountedSubscriptionSuccess()" in RunnerTests failed with:
Asynchronous wait failed: Exceeded timeout of 5 seconds, with unfulfilled expectations: "Purchase request should succeed".

Log:
https://logs.chromium.org/logs/flutter/buildbucket/cr-buildbucket/8705574999958128353/+/u/Run_package_tests/native_test/stdout

xcresult:
https://storage.googleapis.com/flutter_logs/flutter/2882e3cc-24c5-4f8c-8c58-810b429263a0/drive%20examples/2882e3cc-24c5-4f8c-8c58-810b429263a0/xcodebuild-2025-08-25T02:36:00.840151.zip

[flutter-triage-bot]

This issue is assigned to @LouiseHsu but has had no recent status updates. Please consider unassigning this issue if it is not going to be addressed in the near future. This allows people to have a clearer picture of what work is actually planned. Thanks!

[stuartmorgan-g]

This is a significant source of the flake in flutter/packages, which makes PRs (especially rolls) harder to land. If this isn't going to be resolved soon (which seems unlikely), please disable the tests until they are fixed.