Remove the `counts.in_review_folder` metric
Proposal
We can remove the counts.in_review_folder
metric as while it provides data about environments under a "review" folder, it does not provide overall data about environments, including variants of review even when the use case is the same (e.g. no "test" folder is checked).
Documentation on how to remove a metric: https://docs.gitlab.com/ee/development/internal_analytics/service_ping/metrics_lifecycle.html#remove-a-metric