fix(测试跟踪): 测试计划功能用例列表用例等级排序报错

--bug=1019253 --user=宋昌昌 [测试跟踪]测试计划-功能用例-用例等级排序提示sql错误 https://www.tapd.cn/55049933/s/1285934

test-track/backend/src/main/java/io/metersphere/base/mapper/ext/ExtTestPlanTestCaseMapper.xml

@@ -270,7 +270,7 @@
             order by
             <foreach collection="request.orders" separator="," item="order">
                 <choose>
-                    <when test="order.name == 'custom_num' || order.name == 'num' || order.name == 'name'">
+                    <when test="order.name == 'custom_num' || order.name == 'num' || order.name == 'name' || order.name == 'priority'">
                         test_case.${order.name} ${order.type}
                     </when>
                     <otherwise>