完成 getAllGroupIds 逻辑

src/main/java/com/ruoyi/device/service/impl/GroupServiceImpl.java

@@ -112,6 +112,7 @@ public class GroupServiceImpl implements IGroupService
     @Override
     public List<Long> getAllGroupIds()
     {
-        return null;
+        List<Group> groupList = groupDomain.selectGroupList(new Group());
+        return groupList.stream().map(Group::getGroupId).toList();
     }
 }