fix(测试跟踪): 修复复制功能用例责任人变更问题

--bug=1028407 --user=王旭 【测试跟踪】功能用例-复制到-选择模块-复制过去的用例责任人发生变更 https://www.tapd.cn/55049933/s/1403922

test-track/backend/src/main/java/io/metersphere/service/TestCaseService.java

@@ -3224,7 +3224,7 @@ public class TestCaseService {
                 testCase.setNum(nextNum++);
                 testCase.setCasePublic(false);
                 testCase.setCreateUser(SessionUtils.getUserId());
-                testCase.setMaintainer(SessionUtils.getUserId());
+                testCase.setMaintainer(testCase.getMaintainer());
                 testCase.setReviewStatus(TestCaseReviewStatus.Prepare.name());
                 testCase.setStatus(TestCaseReviewStatus.Prepare.name());
                 testCase.setLastExecuteResult(null);