`unawaited_futures` not working in `forEach`

[mgenware]

Describe the issue

Try calling an async func in forEach:

Expected behavior

• If forEach supports async callbacks, if should report unawaited_futures
• If not, it should warn that the async function param might not be awaited

Additional context

Flutter (Channel stable, 3.22.2, on macOS 14.5 23F79 darwin-arm64, locale
en-US)

[srawlins]

Thanks for the report! This is a case of #57653