[3.1] ask_exec(): no longer skip exec events in hats
Instead of ignoring all exec events that happen in a hat/child profile, only disallow child exec. ix and px are valid options inside a hat and are now offered to the user.
(When the tools support nested child profiles one day, we can even allow child exec again.)
Backported from dfb6f90a / !1133 (merged) to match the 3.1 branch