Add CI jobs to disable security issue processor schedule

What does this MR do and why?

Describe in detail what your merge request does and why.

Content

• Add CI jobs to disable security issue processor schedule

Before running the default merge chatops command, we want to disable the security-target issue processor pipeline schedule to ensure no other issues are linked to the security tracking issue and no linked issues are inadvertently unlinked after this point.

Ref: gitlab-com/gl-infra/delivery#20428 (closed)

Testing

Pipeline creation

This was tested in this repo (gitlab-org/release-tools), just to see that the pipeline gets created as we expect it.

With SECURITY_RELEASE_PIPELINE=true	With SECURITY_RELEASE_PIPELINE='disable_issue_processor'
As you can see, the new jobs are before the early_merge step
Pipeline	Pipeline

Configuration and execution testing

This job is safe to test both configuration and execution at the same time, since it only disables a pipeline schedule, that we can reenable after testing. This test is done one ops instance.

• Unprotect and delete the branch on ops after testing

Step	Screenshot
Initialized as manual pipeline (Pipeline) IS_TESTING = true SECURITY_RELEASE_PIPELINE = disable_issue_processor
After security_release_disable_issue_processor_schedule:start is manually triggered
Slack notification (Link)
After security_release_disable_issue_processor_schedule:start completed successfully, it started security_release_disable_issue_processor_schedule:execute (job log)
The pipeline schedule was: Changed ownership to the Release Bot user Disabled