This mostly fixes an issue I was seeing with creating code monitors for
multiple repos where we'd get weird conn busy errors. Basically, the
issue is that transactions can't be used concurrently and the
database.DB passed into this function is a transaction in
CreateCodeMonitor. The jobs run in parallel, which triggers these
errors sporadically.
The fix is incomplete and hacky, but I'm struggling to figure out a way
to not pass in a transaction here or to guarantee that the transaction
is never used concurrently, so I'm opting for the quick fix for the moment.
Test plan
Tested manually that creating a code monitor for many repos doesn't cause conn busy (at least not nearly as much).
