Add retried jobs to pipeline stages

What does this MR do?

Add new property required in Projects::PipelinesController#stage.json response which will list all the retried jobs for that specified stage.

What are the relevant issue numbers?

gitlab-org/gitlab-ce#50461

gitlab-org/gitlab-ce#50101

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides

Closes #50461 (closed)