Update ActiveRecord adapter for changes introduced by ActiveRecord 7.1

[yasirazgar]

This PR fixes ActiveRecord::Base.clear_active_connections! for active_record 7.2, but this is deprecated in version 7.1 itself.

DEPRECATION WARNING: Calling `ActiveRecord::Base.clear_active_connections! is deprecated. Please call the method directly on the connection handler; for example: `ActiveRecord::Base.connection_handler.clear_active_connections!`. (called from clear_active_connections! at /usr/local/bundle/gems/activerecord-7.1.5.1/lib/active_record/connection_handling.rb:320) (ActiveSupport::DeprecationException)
    from gems/graphiti-1.7.6/lib/graphiti/adapters/active_record.rb:310:in `close'
    from gems/graphiti-1.7.6/lib/graphiti/scope.rb:49:in `block (2 levels) in resolve_sideloads'
    from gems/concurrent-ruby-1.3.5/lib/concurrent-ruby/concurrent/executor/safe_task_executor.rb:24:in `block in execute'

This should actually check Gem::Version.new("7.2")