Core/Misc: Fix an exploit where moving while consuming something that would fade when the player stands up would stay if the player started moving and using the effect at the same time. Thanks to @FrozenSoul and @jildor.

Fixes #6271
Core/Items: Fix an exploit where the player was able to send CMSG_SET_AMMO with items they didn't have in their bags. Only a visual bug (not sure if it gave bonuses too, which iirc do appear in later expansions).