None[1] of them actually rely on their own onGesture handler, they
all register their own stuff to ReaderUI's.
Hotfix #9710 revealed that the way this was handled didn't exactly
work as expected ;).
The only thing that consumes ges_events is InputContainer's onGesture
method. All these modules *extend* InputContainer, but none of them
*implement* a custom onGesture, so self.onGesture = nil was just a NOP,
they always access InputContainer's method via inheritance.
If we actively want to neuter it, we *have* to implement it in that
module (with a NOP).
[1] The exception being ReaderZooming, but that only when in flip mode.