fix(接口测试): 1.18.3版本的场景导入1.19版本报错

--bug=1011483
--user=郭雨琦
1.18.3版本的场景导入1.19版本报错
https://www.tapd.cn/55049933/bugtrace/bugs/view/1155049933001011483

backend/src/main/java/io/metersphere/api/dto/automation/parse/ApiScenarioImportUtil.java

@@ -212,6 +212,7 @@ public class ApiScenarioImportUtil {
         apiTestCase.setCreateTime(System.currentTimeMillis());
         apiTestCase.setUpdateTime(System.currentTimeMillis());
         apiTestCase.setVersionId(apiDefinition.getVersionId());
+        apiTestCase.setPriority("P0");
         object.put("id", apiTestCase.getId());
         object.put("resourceId", apiTestCase.getId());
         object.put("projectId", projectId);