[FIX] base: Handle custom field under country in contact kanban view

Issue

	- Install "Studio" and "Contact" apps
	- Edit with Studio the Contact Kanban View
	- Add field under city/country

	Field appears only if no city is set.

Cause

	The new field has as anchor the 5th <li> with the field country
	who will appear only if not city is set. However, in case there a city
	AND a country, the 6th <li> will appear instead of 5th (the target one).

Solution

	Let only one <li>, one country and one city field but with the right conditions.

opw-2288545

closes odoo/odoo#54423

Signed-off-by: Nicolas Martinelli (nim) <nim@odoo.com>