[BLOCKED by switching to sidekiq] Redis.current= Deprecation warning

[jcoyne]

Describe the bug
Redis.current= is deprecated and will be removed in 5.0. (called from: /Users/jcoyne85/.rbenv/versions/3.0.3/lib/ruby/gems/3.0.0/gems/redis-namespace-1.8.1/lib/redis/namespace.rb:245:in `initialize')

See resque/redis-namespace#189

This will block our upgrade to the redis gem 5.0

[ndushay]

technically not blocked but pointless if we switch to sidekiq

[jmartin-sul]

made moot by #1984