Update feature_category for the top 1000 slow RSpec tests files

We can get the top 1000 slow RSpec tests group by file from rspec-stats

After we updated the flaky tests metadata #381801 (closed) we can continue with top slow tests.

I think we should update test metadata for the tests which would bring the most value. This would be second step.

Follow-up issue to updated remaining tests #385498 (closed)