Before this commit, if a user tries to group a kanban view by a date or a datetime interval, then tries to drag and drop a record from one column to another, then the web client crashes. This is actually an invalid operation, and is supposed to be disallowed. There is already some code that properly handle the situation. However, the field attribute was not properly read in the case of fields of type date/datetime. Related to Issue: #1911975 Co-authored-by: Mohammed Shekha <msh@openerp.com> closes odoo/odoo#30029