Cleanup of Go workflow

[michalinacienciala]

This PR introduces a couple of cleanup changes in Go workflow, as part of work on RFC-18. Those changes are:

• Moving scan job from gosec.yml to client.yml (there is no need to keep them in separate workflows)
• Adding client- prefix to scan and build-and-test jobs (to avoid confusion in the future with other similar jobs that we may want to add or remove from required list in branch protection settings)
• Removing test result puvblishing step (we've decided to resign from using EnricoMi/publish-unit-test-result-action action, as it worked in a confising way sometimes - was assigning the tests results to incorrect workflows)
• Removing unnecessary comment

[michalinacienciala]

nkuba, following jobs can be configured as required in GitHub's settings:

• client-build-and-test
• client-scan