R1:2bbddb8c0f29

Improve some setInitialValue() behavior for PhortuneMerchants

Summary:
This fixes the permissions issue with D16750, which is actually not really a permissions issue, exactly.

This is the only place anywhere that we use a tokenizer field //and// give it a default value which is not the same as the object value (when creating a merchant, we default it to the viewer).

In other cases (like Maniphest) we avoid this because you can edit the form to have defaults, which would collide with whatever default we…