When the user presses control-C, fish marks a cancellation signal which
prevents fish script from running, allowing it to properly unwind.
Prior to this commit, the signal was cleared in the reader. However this
missed the case where a binding would set $fish_bind_mode which would
trigger event handlers: the event handlers would be skipped because of
the cancellation flag was still set. This is similar to #6937.
Let's clear the flag earlier, as soon as we it's set, in inputter_t.
Fixes#8125.
179073ce62