[FIX] account: Wrong quantity in Invoices analysis

Steps to reproduce:

Create a customer invoice with 2 product A and refund 1 product A.
Display account.invoice.report for this custumer.

Bug:

The quantity should be 1 not 3.

Fine tuning of this commit: e890682656

opw:1868116

addons/account/report/account_invoice_report.py

@@ -113,7 +113,7 @@ class AccountInvoiceReport(models.Model):
                     1 AS nbr,
                     ai.type, ai.state, pt.categ_id, ai.date_due, ai.account_id, ail.account_id AS account_line_id,
                     ai.partner_bank_id,
-                    SUM ((invoice_type.sign * ail.quantity) / u.factor * u2.factor) AS product_qty,
+                    SUM ((invoice_type.sign_qty * ail.quantity) / u.factor * u2.factor) AS product_qty,
                     SUM(ail.price_subtotal_signed * invoice_type.sign) AS price_total,
                     SUM(ABS(ail.price_subtotal_signed)) / CASE
                             WHEN SUM(ail.quantity / u.factor * u2.factor) <> 0::numeric
@@ -144,7 +144,11 @@ class AccountInvoiceReport(models.Model):
                          WHEN ai.type::text = ANY (ARRAY['in_refund'::character varying::text, 'in_invoice'::character varying::text])
                             THEN -1
                             ELSE 1
-                        END) AS sign
+                        END) AS sign,(CASE
+                         WHEN ai.type::text = ANY (ARRAY['out_refund'::character varying::text, 'in_invoice'::character varying::text])
+                            THEN -1
+                            ELSE 1
+                        END) AS sign_qty
                     FROM account_invoice ai
                 ) AS invoice_type ON invoice_type.id = ai.id
         """