Canceled viability test
InventoryViability currently supports PENDING, CONCLUSIVE and INCONCLUSIVE states. In support#326 (closed) we discuss the need for canceling a viability test.
A new CANCELED state is defined. When a viability test is canceled, then percentViable must be set to null.
UI updates
On the Viability page we have a button to "Finish test" when incomplete. Add a button "Cancel test" that will first prompt the user "Are you sure you want to cancel this viability test?" and then call the API cancel endpoint.
The edit form should also have "Canceled" as one of the status options.
