Follow-up from "ci: add unit-test task and avoid building the binary"

As per comment in !782 (comment 991701342) , it looks like we're reusing gotest.tools/gotestsum@$(GOTESTSUM_VERSION) in all tests, including the race check. Probably, we can further improve this by either downloading gotestsum in the download deps job or by combining the job somehow. For example, running both unit-test and acceptance tests with the -race flag on