fix: NPCs no longer magically aware of explosives they can't see

[chaosvolt]

Purpose of change

This fixes NPCs being able to see and react to explosives they have no way of knowing are present on the other side of a wall, which negates a lot of the !!FUN!! of dynamic entry.

Describe the solution

In npcmove.cpp, set npc::find_dangerous_explosives so that the NPC in question continues on and dismisses positions that they aren't able to actually see.

Describe alternatives you've considered

Adding an extra layer to this by figuring out how to check whether the NPC is in range to hear the tick sound being given off, and if so allow them to still flee.

Testing

1. Compiled and load-tested.
2. Spawned in a refugee center.
3. Deployed some C-4 on the other side of a wall from an NPC who couldn't see it.
4. The poor sod obvliously gets toasted.
5. Dropped C-4 where the NPC can see it.
6. They still correctly call it out and flee.
7. Checked affected file for astyle.

teehee:

no teehee:

Additional context

Checklist