[FIX] mrp: modify linked move remove quantity done

- create product comp1
- create product finished1
- created bom: 1 comp1 for 1 finished1
- activate PBM
- 100 units of comp1 in stock
- create an MO for 5
- on the pbm, deliver 3 and no backorder
- on the mo, check availability, produce 3
- on the pbm, unlock, change delivered qty from 3 to 5

On the mo, the raw move is reserved to 5 units but the 3 units
used in the first produce are removed.

It happens because editing the quantity or initial on a move
will try to reserve the next moves. In order to reserved,
_do_unreserve will destroy the stock.move.line and _action_assign
(call just after) will recreate them in order to regenerate the
reservation. In the process the qty_done on the stock.move.line will
be loss. We want to avoid this behavior in mrp so we call
_decrease_reserved_quantity from mrp that will keep stock.move.line
with quantity done.

opw-2206472

closes odoo/odoo#47439

X-original-commit: eb43bfa65327661e56a08ccd7f15a04deedc0799
Signed-off-by: Arnold Moyaux <amoyaux@users.noreply.github.com>