Remove the concept of a "security release" from the auto-deploy process
Once #1101 (closed) is completed and auto-deploy branches are only created and dealt with in the Security remote, we no longer need special cases for a "security auto-deploy release", since every auto-deploy interaction is treated as potentially sensitive, due to the nature of &109 (closed).
Removing this distinction allows us to simplify the auto-deploy logic in release-tools. See https://gitlab.com/gitlab-org/release-tools/-/issues/475 for one example.
Edited by Robert Speicher