addon should have unit price editable
Currently, when editing/adding a subscription in the GUI, you cannot edit the unit price of an addon. You can only edit the total amount. So if I want to override the price, and I update the qty, I have to do the math myself and put in the total, rather than just being able to put in the qty and unit price and let it do the math for me. You can do this already on the plan, but not the addon.