fix(测试用例): 关联缺陷列表未按照ID降序

--bug=1041502 --user=宋昌昌 【功能用例】&【测试计划】关联缺陷窗口-缺陷列表数据未按ID降序排列 https://www.tapd.cn/55049933/s/1530554

backend/services/bug-management/src/main/java/io/metersphere/bug/mapper/ExtBugMapper.xml

@@ -125,6 +125,7 @@
         select associate.${bugColumnName} from ${table} associate  where  associate.${sourceName} = #{request.sourceId}
         )
         <include refid="queryWhereConditionByProvider"/>
+        ORDER BY b.num DESC
     </select>
 
     <select id="getIdsByProvider" resultType="java.lang.String">