[FIX]Fixed the issue of group counter, when kanban record dragged from o...

...ne group to another it should update the group length

Task: https://www.odoo.com/web#id=10048&view_type=form&model=project.task&menu_id=3942&action=327
Pad: https://pad.odoo.com/p/r.iKws0chd8JBBQY5U