Reorder primary key columns for ci_runner_machine_builds

What does this MR do and why?

Related to gitlab-com/gl-infra/production#8547 (comment 1316698620)

It fixes the order of the PK columns so that will be possible to filter efficiently only by id and keeps it consistent with the other partitioned CI tables.

Closes #397014 (closed)

How to set up and validate locally

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

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