Remove benchmark require

Deprecated in Rails 8.1, and seemingly not used, so we can remove it.

Author: gmcgibbon

lib/active_resource/connection.rb

@@ -1,6 +1,5 @@
 # frozen_string_literal: true
 
-require "active_support/core_ext/benchmark"
 require "active_support/core_ext/object/inclusion"
 require "net/https"
 require "date"