Add blocks deployments label to incident escalated to a S1 or S2
As part of the incident review for Incident Review: 500 error when sign-in with SA... (gitlab-com/gl-infra/production#17678 - closed), it was noticed that the incident was escalated from severity3 to severity2 . Generally incidents created severity1 and severity2 automatically get the blocks deployment
label but this doesn't seem to have occured when just the severity was escalated.
The blocked deployment may have helped roll back the previous change for faster mitigation but couldn't as the subsequent deployment migrations had started in parallel.