fix(测试用例): 导出用例子模块未导出问题

--bug=1046089 --user=王旭 【测试用例】github#32941导出excle格式的用例，导出是选择了所属模块，但是excle中所属模块内容为空 https://www.tapd.cn/55049933/s/1574745

backend/services/case-management/src/main/java/io/metersphere/functional/service/FunctionalCaseFileService.java

@@ -882,7 +882,17 @@ public class FunctionalCaseFileService {
      */
     private Map<String, String> getModuleMap(String projectId) {
         List<BaseTreeNode> moduleTree = functionalCaseModuleService.getTree(projectId);
-        Map<String, String> moduleMap = moduleTree.stream().collect(Collectors.toMap(BaseTreeNode::getId, BaseTreeNode::getPath));
+        Map<String, String> moduleMap = buildModuleMap(moduleTree, new HashMap());
+        return moduleMap;
+    }
+
+    private Map<String, String> buildModuleMap(List<BaseTreeNode> moduleTree, Map<String, String> moduleMap) {
+        for (BaseTreeNode treeNode : moduleTree) {
+            moduleMap.put(treeNode.getId(), treeNode.getPath());
+            if (CollectionUtils.isNotEmpty(treeNode.getChildren())) {
+                buildModuleMap(treeNode.getChildren(), moduleMap);
+            }
+        }
         return moduleMap;
     }