Investigate if the index_environments_on_name_varchar_pattern_ops index is being used and still needed

Follow up from the !96774 (merged)

It looked like the index is still being used, not much though:

https://thanos-query.ops.gitlab.net/graph?g0.expr=sum(rate(pg_stat_user_indexes_idx_scan%7Benv%3D%22gprd%22%2C%20indexrelname%3D%22index_environments_on_name_varchar_pattern_ops%22%7D%5B1h%5D))&g0.tab=0&g0.stacked=0&g0.range_input=1w&g0.max_source_resolution=0s&g0.deduplicate=1&g0.partial_response=1&g0.store_matches=%5B%5D&g0.end_input=2022-09-05%2008%3A02%3A03&g0.moment_input=2022-09-05%2008%3A02%3A03

Once !96774 (merged) is merged it would be nice to check and see if the index is being used. If not, we can remove it and save some space/time on DML queries.