Reapply "Use shorthand configuration access"

This reverts commit 866c888.

It's missing a require_relative

Author: bouwkast

lib/datadog/tracing/contrib/active_support/cache/events/cache.rb

@@ -81,7 +81,7 @@ def on_start(span, event, _id, payload)
 
                 span.set_tag('EVENT', event)
 
-                set_cache_key(span, key, mapping[:multi_key]) if Datadog.configuration.tracing[:active_support][:cache_key_enabled]
+                set_cache_key(span, key, mapping[:multi_key]) if configuration[:cache_key_enabled]
               rescue StandardError => e
                 Datadog.logger.error(e.message)
                 Datadog::Core::Telemetry::Logger.report(e)

lib/datadog/tracing/contrib/active_support/cache/instrumentation.rb

@@ -3,6 +3,7 @@
 require_relative '../../../../core/utils'
 require_relative '../../../metadata/ext'
 require_relative '../ext'
+require_relative 'event'
 
 module Datadog
   module Tracing
@@ -59,7 +60,7 @@ def trace(action, store, key: nil, multi_key: nil)
 
                 span.set_tag(Ext::TAG_CACHE_BACKEND, store) if store
 
-                set_cache_key(span, key, multi_key) if Datadog.configuration.tracing[:active_support][:cache_key_enabled]
+                set_cache_key(span, key, multi_key) if configuration[:cache_key_enabled]
 
                 yield
               end