Sort secondarily off of id for identical name stability (#5339)

Which fixes flaky tests if nothing else

Author: awwaiid

app/controllers/partners/children_controller.rb

@@ -101,7 +101,7 @@ def sort_direction
 
     helper_method :sort_column # used in SortableHelper
     def sort_column
-      Child.column_names.include?(params[:sort]) ? params[:sort] : "last_name"
+      Child.column_names.include?(params[:sort]) ? params[:sort] : "last_name, id"
     end
 
     helper_method :fetch_valid_item_name

app/controllers/partners/families_controller.rb

@@ -100,7 +100,7 @@ def sort_direction
     end
 
     def sort_column
-      Family.column_names.include?(params[:sort]) ? params[:sort] : "guardian_last_name"
+      Family.column_names.include?(params[:sort]) ? params[:sort] : "guardian_last_name, id"
     end
 
     def archive_children