Add a failing spec for GLQL queries failing when SLIs are initialized

Add a failing spec for GLQL queries failing when SLIs are initialized

I believe this is the problem we were seeing. In tests, the initializers don't run, so no SLIs are initialized, this spec should force the problem to happen.

I can't test this locally right now, because Crowdstrike seems to have broken my setup.

Fix glql errors by adding error_type: nil to apdex labels

This explicitly adds error_type: nil to the apdex recording. In Prometheus this will be the same as not specifying the label at. For Prometheus this means error_type="".

This is for incident: https://app.incident.io/gitlab/incidents/348