Add Gitaly update task security pipeline job

💡 What does this MR do and why?

We are working to automate the final steps of the security release.

This MR adds a new job security_release_finalize:enable_gitaly_update_task to the finalize stage of the security release pipeline. This job will enable the gitaly update task pipeline schedule on the release tools project in the ops instance.

Related to gitlab-com/gl-infra/delivery#19441 (closed)

🚧 Testing

To test, I:

1. Pushed a modified branch to the ops instance and protected it
2. Disabled the components:update_gitaly schedule
3. Ran a pipeline with SECURITY_RELEASE_PIPELINE: finalize as a variable

Description	Reference
Pipeline	https://ops.gitlab.net/gitlab-org/release/tools/-/pipelines/2149808
Job	https://ops.gitlab.net/gitlab-org/release/tools/-/jobs/10697022
Pipeline schedule disabled before the test
Pipeline schedule re-enabled after the test
Slack output

🛃 Author Check-list

• [-] Has documentation been updated?