Doctrine error on removeAdjustement (A managed+dirty entity)

[Jgrasp]

Sylius version affected: 1.12.14

Description
When removing adjustments, if two $entityManager->flush() are played in succession, the following doctrine message appears:

A managed+dirty entity App\Entity\Order\Adjustment@11699 cannot be scheduled for insertion.

This is because shipping adjustments are not removed from the shipment when removing adjustments at the order level.

Steps to reproduce

Use the endpoint /shop/orders/{tokenValue}/complete
Add a new callback on complete transition & send an email.

Email will be send via messenger, an a flush() will be played a first time.
ApiPlatform will also use messenger for this action and will flush() too.

Possible Solution

public function removeAdjustment(AdjustmentInterface $adjustment): void
    {
        if (!$adjustment->isLocked() && $this->hasAdjustment($adjustment)) {
            $this->adjustments->removeElement($adjustment);
            $this->subtractFromAdjustmentsTotal($adjustment);
            $adjustment->setAdjustable(null);
           
             // Here the fix
            $adjustment->setShipment(null);
            
            $this->recalculateAdjustmentsTotal();
        }
    }