fix(vpn): Update `to_field_name` in bulk import form

Changes the value of `to_field_name` from `name` to `address` in the
VPN bulk import form. This ensures proper mapping and validation for
IP address selection during the bulk import process.

Closes #20238

netbox/vpn/forms/bulk_import.py

@@ -107,7 +107,7 @@ class TunnelTerminationImportForm(NetBoxModelImportForm):
         label=_('Outside IP'),
         queryset=IPAddress.objects.all(),
         required=False,
-        to_field_name='name'
+        to_field_name='address'
     )
 
     class Meta: