chore: Remove outdated SAST benchmarking job
What does this MR do?
Our old sast benchmarking job is outdated and can occasionally lead to pipeline failures, like https://gitlab.com/gitlab-org/security-products/sast-benchmark/-/pipelines (most recently due to an expired PAT but I don't even remember what that PAT is going to).
This was introduced 2 years ago and has mostly been ignored since we don't tend to use the benchmarks consistently. Additionally ongoing efforts towards better benchmarking is likely to replace it
See !104 (merged) where it was originally introduced
What are the relevant issue numbers?
n/a
Does this MR meet the acceptance criteria?
Edited by Lucas Charles