Revert "Enable request queuing tracking in Datadog"

This reverts commit 91e5276140.

config/initializers/datadog.rb

@@ -3,9 +3,7 @@ if ENV['DATADOG_RAILS_APM']
     c.use :rails, service_name: 'rails'
     c.use :delayed_job, service_name: 'delayed_job'
     c.use :dalli, service_name: 'memcached'
-
     c.analytics_enabled = true
     c.runtime_metrics_enabled = true
-    c.request_queuing = true
   end
 end