Add pipeline tiers dummy jobs

Context

Workaround to continue working on gitlab-org/quality/engineering-productivity/team#497 (closed), until https://gitlab.com/gitlab-data/analytics/-/issues/20625 is resolved (it might take weeks)

What does this MR do?

To gather pipeline tiers data/insights early, this MR adds dummy jobs with the name of the pipeline tier they are running in.

This way, we'll be able in Snowflake to know which tier the given pipeline is in.

Migration path

As soon as https://gitlab.com/gitlab-data/analytics/-/issues/20625 is closed, and we have access to the pipeline name, we'll be able to change the SQL queries to use the pipeline name.

I don't have a big interest in keeping the very early historical data, so I would just use the pipeline name as soon as we have it, and consider this the first pipeline tiers.

MR acceptance checklist

Please evaluate this MR against the MR acceptance checklist. It helps you analyze changes to reduce risks in quality, performance, reliability, security, and maintainability.

Screenshots or screen recordings

Screenshots are required for UI changes, and strongly recommended for all other merge requests.

Before	After

How to set up and validate locally

Numbered steps to set up and validate the change are strongly suggested.