fix(active-job) Prefix ::ActiveSupport when installing the instrument…

…ation

Otherwise, `ActiveSupport` ends up resolving to `OpenTelemetry::Instrumentation::ActiveSupport`.

`OpenTelemetry::Instrumentation::Registry#install_instrumentation` rescues the exception, so the prepend ends up being (somewhat) silently dropped.

instrumentation/active_job/lib/opentelemetry/instrumentation/active_job/instrumentation.rb

@@ -71,7 +71,7 @@ def require_dependencies
         def patch_activejob
           Handlers.subscribe
 
-          ActiveSupport.on_load(:active_job) do
+          ::ActiveSupport.on_load(:active_job) do
             ::ActiveJob::Base.prepend(Patches::Base) unless ::ActiveJob::Base <= Patches::Base
           end
         end