Fix faulty grafana targets in Verify Dashboard

We had an issue with product dashboards not rendering any data. This is because since they were created, we added a new subvalue called testname (which has a value of .gitlab and we need to add this in order to show data.

./test-dashboard.sh product/verify.dashboard.jsonnet

Installed https://dashboards.gitlab.net/dashboard/snapshot/pJ3FEMpIHLFwI0MLUlSWeerORu0JZqyO - product: Performance - Verify

Before	After