Current behaviour :
When creating a leave type with both approval required for allocation and then setting allocation to 'Set by time off officer', we still require 2 approvals.

Behaviour after PR :
Leave type with allocation set to 'Set by time off officer' will only require one approval as expected.

opw-2671540

closes odoo/odoo#79718

Signed-off-by: Kevin Baptiste <kba@odoo.com>