cnp: pass wayland drop event size to handler, do not nul terminate drop data
cnp: pass wayland drop event size to handler, do not nul terminate drop data

performing strlen() on potential non-string data is not recommended and can
even lead to crashes. nul terminating non-string data is pointless and enables
bad application behavior such as calling strlen() on potentially non-string data

@fix

rvandegrift/elementary,rvandegrift/elementary,rvandegrift/elementary,rvandegrift/elementary