Redis gem instrumentation: add better error handling around v5+ specific instrumentation

[fallwith]

v8.13.0 of the agent introduced support for v5 of the redis gem, and v8.13.1 followed to address a Sidekiq v7 specific use case.

Now with v8.13.1, we have had reports of additional issues that the agent has when attempting to get at the lowest underlying Redis client object within the redis v5 instrumentation.

While we continue to research these reports and attempt to produce reproductions, in parallel or beforehand we should take steps to harden the impacted redis v5 instrumentation to prevent it from crashing. From the customer's perspective, any issue encountered with the Redis v5 instrumentation should result in either parial or no Redis instrumentation with the rest of the agent's functionality continuing to operate normally. Effectively, the error handling should automatically provide at least as good of an experience as rolling back to an agent version that does not have the v5 instrumentation or disabling the instrumentation support in configuration.

[workato-integration]

https://issues.newrelic.com/browse/NEWRELIC-5673