Resolve "Database schema diff 4 - (source) Missing partial index for ci_builds in the source (index_ci_builds_project_id_and_status_for_live_jobs_partial)"

What does this MR do?

Add two missing partial index for ci_builds. This is done according to https://gitlab.com/gitlab-org/gitlab-ce/issues/53994#note_119005184

• We might want to use a better name, but that's what we're using on production at the moment.
• I don't know if this works on MySQL or not? The SQL syntax doesn't seem to work on MySQL is my impression.
• Each migration addition is in its own commit.

What are the relevant issue numbers?

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/53994

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the database guides

Closes #53994 (closed)