GetRecentlyDisconnectedParticipants walked the participant update cache
with Get, which moves each entry to the front of the LRU. Walking from
newest to oldest left the cache in reverse order, so after a reconnect
the next updates evicted the most recently updated participants first.
In a room where the subscriber has tracked 128 or more participants, a
participant that had just disconnected was then dropped from the cache
and a later reconnect did not report it as disconnected, and the
out-of-order version check was lost for recently updated participants.
Use Peek, which reads an entry without changing its recency.