[FIX] purchase: Do not display notes/sections in purchase reporting

The issue is when we create a new PO with notes/sections and these notes/sections are showed on purchase reporting and only the products were supposed to appear there.

This issue happens because the SQL query wasn't applying any filter to the lines. The solution is apply a filter by display_type.

Steps to reproduce:
1) Go to Purchase App -> Purchase Orders -> Create a new PO with notes/sections
2) Go to Reporting -> View as pivot
3) You'll be able to see the section/notes you just created

closes odoo/odoo#118020

Opw: 3245933
Signed-off-by: Adrien Widart <awt@odoo.com>

addons/purchase/report/purchase_report.py

@@ -62,7 +62,7 @@ class PurchaseReport(models.Model):
     @property
     def _table_query(self):
         ''' Report needs to be dynamic to take into account multi-company selected + multi-currency rates '''
-        return '%s %s %s' % (self._select(), self._from(), self._group_by())
+        return '%s %s %s %s' % (self._select(), self._from(), self._where(), self._group_by())
 
     def _select(self):
         select_str = """
@@ -120,6 +120,12 @@ class PurchaseReport(models.Model):
         )
         return from_str
 
+    def _where(self):
+        return """
+            WHERE
+                l.display_type IS NULL
+        """
+
     def _group_by(self):
         group_by_str = """
             GROUP BY

addons/purchase/tests/test_purchase_order_report.py

@@ -89,6 +89,36 @@ class TestPurchaseOrderReport(AccountTestInvoicingCommon):
         self.assertEqual(round(report[0]['delay']), -10, msg="The PO has been confirmed 10 days in advance")
         self.assertEqual(round(report[0]['delay_pass']), 5, msg="There are 5 days between the order date and the planned date")
 
+    def test_02_po_report_note_section_filter(self):
+        po = self.env['purchase.order'].create({
+            'partner_id': self.partner_a.id,
+            'currency_id': self.currency_data['currency'].id,
+            'order_line': [
+                (0, 0, {
+                    'name': 'This is a note',
+                    'display_type': 'line_note',
+                    'product_id': False,
+                    'product_qty': 0.0,
+                    'product_uom': False,
+                    'price_unit': 0.0,
+                    'taxes_id': False,
+                }),
+                (0, 0, {
+                    'name': 'This is a section',
+                    'display_type': 'line_section',
+                    'product_id': False,
+                    'product_qty': 0.0,
+                    'product_uom': False,
+                    'price_unit': 0.0,
+                    'taxes_id': False,
+                }),
+            ],
+        })
+        po.button_confirm()
+
+        result_po = self.env['purchase.report'].search([('order_id', '=', po.id)])
+        self.assertFalse(result_po, "The report should ignore the notes and sections")
+
     def test_avg_price_calculation(self):
         """
             Check that the average price is calculated based on the quantity ordered in each line