[s1910] EventAI - Define way mobs with difficulty flags behave outside of dungeons

This allows to script mobs for both normal map and dungeon.
In such case for the normal map only the events with normal-difficulty (EFLAG_DIFFICULTY_0) are used.

(based on commit [12378] - 5b4e4d0)

Signed-off-by: Xfurry <xfurry@scriptdev2.com>