In support of the [MVC Standalone Vulnerability objects (Vulnerability Management)](https://gitlab.com/gitlab-org/gitlab/issues/13561) epic, we need to add the ability to confirm a Vulnerability. Specifically, it is needed for the [Notify user in the frontend when a vulnerability is resolved](https://gitlab.com/gitlab-org/gitlab/issues/35860) issue. The specs for the dismiss and resolve services can be found here `ee/spec/services/vulnerabilities/dismiss_service_spec.rb` and here `ee/spec/services/vulnerabilities/resolve_service_spec.rb`