Redis instrumentation: support older redis-client

[fallwith]

Redis instrumentation:

• update call_pipelined_with_tracing to yield early (instead of crashing) if a db value cannot be obtained
• rename _nr_client to _nr_redis_client_config to make it more clear that it holds a config object and not a client object, even though config getters can be called directly on the redis gem's client object
• update _nr_redis_client_config to add support for redis-client gem versions older than v0.11
• update _nr_redis_client_config to raise upon failing to get at the underlying config object
• minor exception handling updates to include class names
• update the unit tests accordingly

resolves #1650
resolves #1671

[fallwith]

One way to reproduce the issue:

1. Create a new Rails 7 app. NOTE: do not use --minimal as it does not prep ActionCable to use Redis for development.
2. Optionally confirm that config/cable.yml is referencing Redis for development.
3. Add newrelic_rpm v8.13.0 or v8.13.1 and redis-client < v0.10 in Gemfile and bundle.
4. Start a redis server.
5. Run bin/rails console and perform the following in the console:

require 'action_cable/subscription_adapter/redis'
server = ActionCable.server
keys = server.config.cable.symbolize_keys 
conn = ActionCable::SubscriptionAdapter::Redis.redis_connector.call(keys)
listener = ActionCable::SubscriptionAdapter::Redis::Listener.new(:redis, nil)
listener.listen(conn)

A reproduction will produce a crash with a stack trace. A success after applying this PR will produce a constantly polling listening process without any errors (hit ctrl-c to stop it from listening).

[kaylareopelle]

Thanks for the nil value adjustment! The comments are all suggestions/questions that don't need to be addressed. Feel free to disregard and merge.

[hannahramadan]

makes sense!

[github-actions]

SimpleCov Report

	Coverage	Threshold
Line	93.23%	93%
Branch	84.52%	84%