Reconcile unit tests in multivariant libraries

[ZacSweers]

Currently our ciUnitTest lifecycle tasks only depend on the release variant of tests in libraries, but multi-variant libraries could run their tests in other variants too.

Let's do two things

1. Make ciUnitTest depend on the test task and not just the release test task. This seems like a legacy holdover.
2. Disable the non-release unit tests by default and add a property to optionally enable them if this is desirable