Change behavior ActionController::Parameters#require when value is empty

When the value for the required key is empty an ActionController::ParameterMissing is raised which gets caught by ActionController::Base and turned into that 400 Bad Request reply with a message in the body saying the key is missing which is misleading.

With these changes in that case ActionController::EmptyParameter will be raised which ActionController::Base will catch and turned into that 400 Bad Request reply with a message in the body saying the key value is empty.