Prevent testprof from starting a transaction in migrations specs

What does this MR do and why?

We discovered that migration specs were running inside a transaction because of testprof. This changes the adapter in migration specs so no transaction is initiated

How to set up and validate locally

Running the following spec in master should raise a timeout error

bundle exec rspec spec/migrations/20220606080509_fix_incorrect_job_artifacts_expire_at_spec.rb --seed 27865

You shouldn't get an error with this commit

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.