[FIX]purchase_requisition: Creating requistions from OP

Steps to reproduce the bug:

- Create a product : stockable + purchase : propose a call for tenders + reordering rule (qty min 0, max 0, multiple 1)
- Create a SO for that product.
- Run the scheduler once : a requistion is generated (Purchases > Purchase > Purchase Agreements), which is normal behavior
- Run the scheduler a second time

Bug:

A new requistion was generated for the same product, by the same reordering rule

opw:1892950

closes odoo/odoo#28611

addons/purchase_requisition/models/purchase_requisition.py

@@ -337,3 +337,14 @@ class ProcurementRule(models.Model):
         values['picking_type_id'] = self.picking_type_id.id
         self.env['purchase.requisition'].create(values)
         return True
+
+class Orderpoint(models.Model):
+    _inherit = "stock.warehouse.orderpoint"
+
+    def _quantity_in_progress(self):
+        res = super(Orderpoint, self)._quantity_in_progress()
+        for op in self:
+            for pr in self.env['purchase.requisition'].search([('state','=','draft'),('origin','=',op.name)]):
+                for prline in pr.line_ids.filtered(lambda l: l.product_id.id == op.product_id.id):
+                    res[op.id] += prline.product_uom_id._compute_quantity(prline.product_qty, op.product_uom, round=False)
+        return res