The LUA script in the Sidekiq duplicate job middleware attempts to
update the deduplicated flag in a msgpack-serialized cookie. When it
writes back the key, it also tries to maintain the existing TTL.
However, if the TTL becomes 0, then Redis will raise an error:
"@user_script:7: ERR invalid expire time in set".

When we lowered the deduplication TTL of
`::Namespaces::ProcessSyncEventsWorker`from 6 hours to 1 minute in
!120580, this
exposed a bug in the LUA script because the tests repeatedly call this
middleware. To fix this, we don't bother writing back the key if the
TTL is not > 0.

Relates to #411325