No way to create piece for pending order with manual create piece = True

Overview:
Steps to Reproduce:

1. Create order (status Pending)
2. Create order line (Manual create pieces = True)
3. Open receiving and select title connected to previously created order line 
4. Press Add piece
5. Save piece

Expected Results:

Piece is created (it's allowed to create pieces for pending order with line Manual create pieces = True)
Actual Results:

BE validation is thrown that piece creation is forbidden for pending order