fix(测试跟踪): 测试计划用例列表展示用例等级字段

--bug=1018325 --user=宋昌昌 【测试跟踪】测试计划-功能用例列表没有用例等级字段 https://www.tapd.cn/55049933/s/1281068

test-track/frontend/src/business/utils/track-table-header.js

@@ -5,6 +5,7 @@ const TRACK_HEADER = {
   TEST_PLAN_FUNCTION_TEST_CASE: [
     {id: 'num', key: '1', label: 'commons.id'},
     {id: 'name', key: '2', label: 'commons.name'},
+    {id: 'priority', key: '3', label: 'test_track.case.priority'},
     {id: 'versionId', key: 'b', label: 'project.version.name', xpack: true},
     {id: 'tags', key: '3', label: 'commons.tag'},
     {id: 'nodePath', key: '4', label: 'test_track.case.module'},