don't assume query.selected_operation is defined

Author: redterror

lib/graphql/tracing/sentry_trace.rb

@@ -41,7 +41,9 @@ def instrument(keyword, object)
                 if query.selected_operation_name
                   span.set_data('graphql.operation.name', query.selected_operation_name)
                 end
-                span.set_data('graphql.operation.type', query.selected_operation.operation_type)
+                if query.selected_operation
+                  span.set_data('graphql.operation.type', query.selected_operation.operation_type)
+                end
               end
             end