Run tests in kotlin-ci.yml

[haywood]

#1542 adds .github/workflows/kotlin-ci.yml, which builds the kotlin SDK on push and pull request.

We should further configure the workflow so that it can run the tests, similar to go-ci.yml and python-ci.yml.

We may also wish to consider factoring a re-usable setup-looker-instance.yml action out of these two workflows to simplify this process going forward.

[drstrangelooker]

Can we change this back to p3? p1s and p2s will trigger SLO monitoring after sync to buganizer.