Fix error when using non-ActiveRecord::Base on ActiveRecord::Relation

[stephannv]

It seems like a wrong way to build Literal::TypeError

NoMethodError (undefined method 'expected' for class Literal::TypeError):

literal (1.4.0) lib/literal/rails/patches/active_record.rb:7:in 'ActiveRecord::RelationType#initialize'
literal (1.4.0) lib/literal/rails/patches/active_record.rb:29:in 'Class#new'
literal (1.4.0) lib/literal/rails/patches/active_record.rb:29:in 'ActiveRecord.Relation'