Allow Release Tools bot to retry failed Gitaly pipelines

Context

This is a follow-up to #6143 (comment 1987927818), to further reduce the amount of manual intervention required on part of the Gitaly team.

Proposal

Allow the Release Tools bot to retry failed pipelines in Update Gitaly version MRs. Failed pipelines are typically caused by flakey tests outside of the purview of the Gitaly team.

Retrying up to 3 times feels reasonable. It would be great if the bot can retry the specific failed job rather than running the entire pipeline from scratch.