feat:添加687实验，修复B8特征获取不到的问题

ad-engine-service/src/main/java/com/tzld/piaoquan/ad/engine/service/score/impl/RankServiceImpl.java

@@ -1,5 +1,6 @@
 package com.tzld.piaoquan.ad.engine.service.score.impl;
 
+import com.alibaba.fastjson.JSON;
 import com.alibaba.fastjson.JSONObject;
 import com.tzld.piaoquan.ad.engine.commons.score.ScoreParam;
 import com.tzld.piaoquan.ad.engine.commons.score.ScorerUtils;