exclude no variant attributes from simple variant wizard

reason: attributes with detailed type set as multi are
cosidered as no variant, hence no variants are created
for them. This ensures variants products purchased are
aligned with SOs.

without this fix, product variants including multi type
attributes results in received stocks for POs not being
consumable by SOs sharing matching configurable options

product_simple_variant_builder/wizards/wizard_simple_create_variant.py

@@ -50,6 +50,9 @@ def _onchange_product_tmpl(self):
         if self.product_tmpl_id:
             lines = line_model.browse()
             pending_variants = self.product_tmpl_id.attribute_line_ids
+            pending_variants = pending_variants.filtered(
+                lambda tmpl_att_line: tmpl_att_line.attribute_id.display_type != "multi"
+            )
             for line_data in [
                 {
                     "attribute_id": attribute_line.attribute_id.id,
@@ -142,7 +145,9 @@ class WizardCreateVariantLine(models.TransientModel):
         required=False,
     )
     attribute_id = fields.Many2one(
-        comodel_name="product.attribute", string="Attribute", required=False
+        comodel_name="product.attribute",
+        string="Attribute",
+        required=False,
     )
     attribute_value_ids = fields.Many2many(
         comodel_name="product.attribute.value",