Spike: Investigate `autostart.denylisted_constants`

After reports #2677 and #2623, we've determined that we may need to have a better approach to excluding agent start-up from certain contexts.

Investigate Rails::Command::RakeCommand to understand how we may be able to exclude specific rake tasks from autostarting the agent in a Rails context
Consider the benefits of changing the type of autostart.denylisted_constants to an Array (this would need to be done as part of a major release)
Consider whether a different configuration option would benefit users, perhaps with an allowlist rather than a denylist
Review the efficacy of autostart.denylisted_rake_tasks in modern versions of Rails

newrelic / newrelic-ruby-agent