fixes #11238

Checking for audit logs generated from workspace builds is flaky since there exists a small gap of time between when the transaction is committed for completing a job and when we write an audit log. In fact this means any test in our coderd package that is asserting build-related audit logs is inherently flaky since we all use the coderdtest.AwaitWorkspaceBuildJobCompleted to indicate it is a good time to check for audit log generation. We should probably remove any workspace build audit log assertions from coderd and test it solely in provisionerdserver.

I opted to move this to use dbfake since that eliminates any raciness with the provisioner's audit logs.