fix: 修复查找用户所在部门特殊情况BUG

laws-module-system/src/main/java/com/jero/modules/system/service/impl/SysUserDepartServiceImpl.java

@@ -157,6 +157,9 @@ public class SysUserDepartServiceImpl extends ServiceImpl<SysUserDepartMapper, S
 	public String getFirstDeptIdByUserId(String userId) {
 		List<DepartIdModel> departIdModels = this.queryDepartIdsOfUser(userId);
 		List<String> departIds = departIdModels.stream().map(DepartIdModel::getKey).collect(Collectors.toList());
-		return departIds.get(0);
+		if (!departIds.isEmpty()) {
+			return departIds.get(0);
+		}
+		return null;
 	}
 }