Investigate and fix conformance progress issue

[kriswest]

The conformance tests are currently reporting one failure for the reference implementation, without any test obviously being failed.

I think that will relate to a 'Mock Intent App A' thats not getting closed properly and causing a timeout..

[russlan23]

I traced this while running the complete automated pack for #2048. The destructured-method scenarios could open Mock Intent App A before its close listener had registered, while cleanup allowed only a one-second response window. #2048 now waits for mock initialization, awaits the close broadcast, and uses the existing mock-processing timeout. After rebasing that branch onto the latest main, the full automated conformance run passed with no failures in 6.0 minutes.

That appears to cover this issue, so I have not opened a separate competing fix.