DEV: Enable unless cops

We discussed the use of `unless` internally and decided to enforce
available rules from rubocop to restrict its most problematic uses.

plugins/chat/spec/support/api_schema_matcher.rb

@@ -9,7 +9,7 @@ RSpec::Matchers.define :match_response_schema do |schema|
       JSON::Validator.validate!(schema_path, object, strict: true)
     rescue JSON::Schema::ValidationError => e
       puts "-- Printing response body after validation error\n"
-      pp object
+      pp object # rubocop:disable Lint/Debugger
       raise e
     end
   end