Make it easier to find errors when scanning output of firehose on a mono repo

[kevmoo]

See https://github.com/dart-lang/build/actions/runs/4536053704/jobs/7992267951?pr=3478

There is an error there – but it's hard to find scrolling through the output.

The package and the error reason should be super clear. Maybe use ansi.dart from pkg:cli?

[jakemac53]

We could possibly use the "group" formatting like we do for tests + some emojis? Each package should be its own thing, and obvious if it failed/succeeded