docket: don't crash on receiving uninstall ack
We should've already deleted it from state by this point.
|= [=desk =^wire]
^- (quip card _state)
~| [%took-for-nonexistent-charge desk]
- ?> (~(has by charges) desk)
+ ?> |((~(has by charges) desk) ?=([%uninstall ~] wire))
=* cha ~(. ch desk)
?+ wire ~|(%bad-charge-wire !!)
::
