feat(balance): don't give mi-gos spawned by nerve clusters free turns

[chaosvolt]

Purpose of change

A thing I noticed is that unleashing the special bonus surprise in mi-go locations tends to get the player stunlocked and killed, due to giving the critter it spawns several free hits on you.

Describe the solution

In map_functions.cpp, set migo_nerve_cage_removal so that the mi-go takes a penalty to moves when spawned, equal to the moves that iexamine::migo_nerve_cluster takes plus 1 turn.

Describe alternatives you've considered

Simply having it not mod your moves on iexamine at all. Most iexamine interactions take a bit of time so it'd be inconsistent, and burning 2 seconds is normally inconsequential given monsters that haven't been spawned out of thin air in that exact instant have normally spent the time you're activating it spending their moves like normal creatures, it just plays weirdly with spawning a monster at the same time.

Testing

1. Compiled and load-tested.
2. Spawned in and activated a nerve cluster, confirmed I don't give it several free hits.
3. Re-tested with smashing it open with a sledgehammer instead, confirmed I don't give it a free hit anymore either that way. Might still give them a cheap shot if the player uses a weapon with an absurdly high movecost, but the amount of free turns needed for the iexamine to not give it a free shot on you should be comfortably high enough to mitigate most instances of this.
4. Checked affected file for astyle.

Additional context

Checklist