This reverts commit b8100ad1ae.
This was causing many issues in CI, including AR connections
not being expired because of threading issues, which was also
causing rails_helper to raise an error because we had busy
connections at the end of spec runs.
```
Cannot expire connection, it is owned by a different thread:
/__w/discourse/discourse/vendor/bundle/ruby/3.1.0/gems/puma-6.0.1/lib/puma/thread_pool.rb:106
sleep_forever>. Current thread: #<Thread:0x00007f541966fcc8 run>.
```
And:
```
Failure/Error: raise ActiveRecord::Base.connection_pool.stat.inspect
RuntimeError:
{:size=>5, :connections=>2, :busy=>2, :dead=>0, :idle=>0, :waiting=>0, :checkout_timeout=>5.0}
```
See https://github.com/discourse/discourse/actions/runs/3825882529/jobs/6509204143
for examples.