Properly remove Vi mode when switching to different bindings

fish_key_bindings may be set directly
or via fish_{default,vi}_key_bindings.

The latter use "set --no-event" to simplify their control
flow.  This (24836f965 (Use set --no-event in the key binding
functions, 2023-01-10)) broke Vi mode cleanup, since Vi mode
uses a variable hook.  Let's update this variable also when using
fish_{default,vi}_key_bindings.  Another reason to keep this variable
in sync is to make the fish_key_bindings handlers working as expected.

share/functions/__fish_change_key_bindings.fish

@@ -1,4 +1,5 @@
 function __fish_change_key_bindings --argument-names bindings
+    set -g __fish_active_key_bindings $bindings
     # Allow the user to set the variable universally
     set -l scope
     set -q fish_key_bindings