Steps
---
1. install `mrp,sales_management`
2. Create a manufacture-routed product P with a manufacturing BOM:
   * Operation OP1, duration = 1 hr
   * some component
3. Create a reording rule for P with a manufacturing route:
   * min qty = 0
   * max qty = 0
4. Create an SO for 15 > Confirm
   * (A MO for 15 P should have been generated)
6. duplicate the SO > Confirm
   * (The **same** MO is now for 30 P)
7. duplicate the SO > Confirm
=> The MO is for 75 P instead of 45

Cause
---
When the reordering rule is triggered, we attempt create a procurement
for the opposite of the forecast quantity of product P and add it to the
MO.
But the reordering rule's visibility days is 0 (default), so once the
MO's expected finished date (now + qty * 1 hr) is tomorrow or more [1]
we do not consider the quantity coming from the MO for the stock
forecast.
Therefore the procurement is for the sum of all the previous orders for
P (ie 15 * 3 = 45), so the MO's quantity will be 30 + 45 = 75 instead of
30 + 15 = 45

[1] (cf commit 1) There is another bug this PR fixes where the date finished
for MOs is not computed at creation time but only at write time,
therefore, we need to be at least on the 3rd SO for the bug to appear.
(The 2nd one writes to the MO)

Fix
---
When computing the quantity in progress for product P, take into account
MOs such that `date_start <= end_of_orderpoint_forecast < date_finished`

\+ [1] Do compute the finished date at creation when it isn't specified in
the vals and do not specify it in the above flow.

opw-4034475