weapon_recurse bugfix

This is the cause of an interaction between Flexible Combat and weapon `attack_recurse` that may cause infinite recursive attack


Cause of this problem:

Currently, recurse attack will not check if current weapon have `attack_recurse` property.

Also, this mechanism use `self.__attacktargetwith_recursing = nil` to mark attack recurse haven't been started / have been ended.

Flexible combat is triggered before recurse attack

So, a flexible combat unarmed attack can consume `self.__attacktargetwith_recursing`, while the later triggered attack thinking we are starting a new attack, recurse again.

You can test this with Flexible Combat + Razorlock.

This is a quick fix, howevr while considering while using the old `if self.__attacktargetwith_recursing or (weapon and weapon.attack_recurse) then` design may also need discussion.

See merge request !631