Let the user remove the work orders from the sale

If the work order is empty (without items), let the user remove it from the
sale.

We are not actually excluding the order from the database, but just
canceling it.

Change-Id: I5ffe7f53e4c84a45d0d88e6f3d372c86c98c8d06
Disable add button in optical item step

The code that disables the new button in the item step of the optical sale
wizard was in the wrong place

Change-Id: Idcd5202c22464ab5d60b276ec5977658c176b0ba
Merge "Let the user remove the work orders from the sale"
Merge "Disable add button in optical item step"