Sonarcloud already does coverage checks in CI but always reports 0% coverage for the repo/rest-api directory. We should update the configuration to correctly check and publish the coverage.
Related gerrit patch and discussion from 2018: https://gerrit.wikimedia.org/r/c/integration/config/+/448560
Related task for enabling code coverage for Wikibase: T288396: [REPO][CLIENT][SW] Re-start Wikibase test coverage reporting