Review parallel count for `rspec *` jobs

These rspec jobs are taking longer than 20 minutes, making them the bottleneck of the test stage:

• rspec integration pg9 https://app.periscopedata.com/app/gitlab/496118/Engineering-Productivity-Sandbox?widget=6914226&udv=833427

Todo:

• review number of specs over time
• increase number of parallel jobs if necessary

The corresponding pg 10 jobs should also be reviewed.

Related #200086 (closed)