[BUG] Stamina based skills are not validated for blocking state when casting

[mFragaBA]

When performing skills we perform some validations (e.g. cd based skills check that the skill is not on cooldown, stamina based check that the wielder has enough stamina available). However when working with bots (#1129 ) I noticed that we're missing some checks. For example, if I didn't restricted it, bots would fire the 3 shots instantly plus the ultimate. We should add these checks in get_skill_if_usable

This is a problem because a cheater could use this to gain an advantage.