[FIX] crm: lead to opportunity no link partner

Have a lead with a partner on it, convert it to opportunity
in the conversion wizard, tick "don't link to customer"

Before this commit, the opportunity has been linked to the
lead's partner

After this commit, the opportunity is not linked to any partner

OPW 2077692

closes #38202

Signed-off-by: Lucas Perais (lpe) <lpe@odoo.com>

addons/crm/wizard/crm_lead_to_opportunity.py

@@ -96,8 +96,12 @@ def _convert_opportunity(self, vals):
         leads = self.env['crm.lead'].browse(vals.get('lead_ids'))
         for lead in leads:
             self_def_user = self.with_context(default_user_id=self.user_id.id)
-            partner_id = self_def_user._create_partner(
-                lead.id, self.action, vals.get('partner_id') or lead.partner_id.id)
+
+            partner_id = False
+            if self.action != 'nothing':
+                partner_id = self_def_user._create_partner(
+                    lead.id, self.action, vals.get('partner_id') or lead.partner_id.id)
+
             res = lead.convert_opportunity(partner_id, [], False)
         user_ids = vals.get('user_ids')