Swap FK ci_unit_tests to projects for LFK

What does this MR do and why?

Per &7249 (closed)

As part of our CI "decomposition" efforts we need to remove all foreign keys that are cross-database (ie. between the planned main and ci databases). We are going to replace them all with "loose foreign keys".

This foreign key have been determined to be safe for swapping to loose foreign keys per #348267 (closed).

Related issue: #348267 (closed)

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