use unstone jstext for string creation

playdate/json_playdate.c

@@ -116,7 +116,7 @@ static void encode_js_object(json_encoder *enc, JSContext *js, JSValue obj) {
             JS_FreeCString(js, key);
             JS_FreeAtom(js, props[i].atom);
         }
-        js_free(js, props);
+        js_free_rt(props);
     }
     enc->endTable(enc);
 }