Create Grafana Helm Test as part of Mimir BB Smoke Test

Mimir integrates with Grafana and Prometheus atm (in the future will include alloy).

Acceptance Criteria

As part of the BB smoke test for Mimir, Mimir repo should include a cypress test that

1. logs into Grafana
2. checks the mimir connections (datasource)
3. checks the prometheus remote write url in the dashboard.

Or as an alternative to the above writing some API tests