chore: add event to metrics tests

[Elfo404]

Follow up to https://github.com/grafana/grafana-ci-otel-collector/pull/144

Add tests for the metrics event handling. the test should make sure that for a given status, datapoints are registered also for all other statuses.

[Elfo404]

@zerok the repo was set up to dismiss stale reviews automatically, sorry 🤦 mind another look plz?

[zerok]

@Elfo404 done 🙂