Only write test output in GitHub actions for test failures

Integration tests have recently moved to GitHub actions. All tests include their output in the console logs. That makes it hard to see details about failures, which are what you really care about.

The test runner should be configured to only include test output in console logs for failures.

I did this in grpc/grpc-dotnet repo, which also uses GH actions, and found it made using console logs much easier. Unfortunatly that repo uses nunit, not xunit, for tests so we'll need to figure out how to configure it in dotnet/aspire.

cc @davidfowl