fix(proxy): memory leak

According to this forum post and the one below it, Snowflake proxy appears to start at 100MB RAM consumption and goes up to 1.5GB.

A fix would be nice, but a catch-all alternative would be to automatically restart the proxy every so often. Maybe add the instructions here https://community.torproject.org/relay/setup/snowflake/standalone/.

UPD: It's probably a duplicate of #40154 (closed).