Replace `bridge-stats-ips` with `bridge-ips`

I believe bridge-stats-ips in the dirspec is actually a typo which goes back all the way to https://gitlab.torproject.org/tpo/core/tor/-/tree/e1e5c1b3aba96afbd6fa3b5ece262720dd45a80e. The correct item is supposed to be bridge-ips.