Write feature spec for environment dashboard

We should add a realistic feature test in ee/spec/features/dashboards/operations_spec.rb otherwise the feature could easily introduce regression in the future.

---

Follow-up from "Environments Dashboard Limits and Optimization"

The following discussion from !19775 (merged) should be addressed:

• @dosuken123 started a discussion: (+1 comment)

  By the way, do we have a feature spec for environments dashboard? ee/spec/features/dashboards/operations_spec.rb seems the place but I don't really see tests against realistic usecase e.g. 3 projects with 3 environments are correctly shown in the page.