Remove deprecated release_pressure metric
What does this MR do and why?
As we have moved to the new patch process, the old delivery dashboard chart that displayed the number of MRs with Pick into
labels has been removed. In this MR, we remove the code that would supply those metrics to Prometheus/Grafana.
Related to gitlab-com/gl-infra/delivery#19157 (closed)
Author Check-list
- [-] Has documentation been updated?
Edited by Steve Abrams