Add text responses as json with msg key

src/endpoints/api_v1_schedules_STR.c

@@ -201,7 +201,7 @@ api_v1_schedules_STR_DELETE(struct mg_connection *nc, struct http_message *hm, e
     }
     else
     {
-        M_RESPONSE_TEXT_STATIC(LOGGER_DEBUG, response, 200, "the target schedule got deleted");
+        M_RESPONSE_MSG(LOGGER_DEBUG, response, 200, "the target schedule got deleted");
     }
     schedule_free(schedule);
     return;