[FIX] calendar: traceback on recurrent meetings when repetition number is 0
[FIX] calendar: traceback on recurrent meetings when repetition number is 0

If the user tries to save the recurrent event with 0 as the number of
repitations or interval there will be a traceback so instead of traceback
display the warning so user will not be able to save that event.

Task-1930809

closes odoo/odoo#31388

Signed-off-by: Nicolas Martinelli (nim) <771435c469f83f6aa9c405ac5e1ed06314a94f2d@odoo.com>
ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo,ygol/odoo