[FIX] website_sale: Correct partner search

8b921471 has introduced wrong context key which replaces `res_partner_search_mode` with the depricated `search_default_customer` which was breaking search functality added by 8766f388 

In this commit we correct context's key.

closes odoo/odoo#50176

Signed-off-by: Jérémy Kersten (jke) <jke@openerp.com>

addons/website_sale/views/sale_order_views.xml

@@ -272,7 +272,7 @@
             <field name="partner_id" position="attributes">
                 <attribute name="context">{
                     'display_website': True,
-                    'search_default_customer': 1,
+                    'res_partner_search_mode': 'customer',
                     'show_address': 1,
                     'show_vat': True,
                 }</attribute>