Fix Spectre first person executions script error

[NachosChipeados]

Fixes R2Northstar/Northstar#418 and the Spectre part of #885.

The reason this happens is because the fp executions code tries to find the "head" bodygroup, but Spectres have "removableHead" instead, so i fixed it by:

1. Decompiling the Spectre model
2. Renaming the "removableHead" bodygroup to "head"
3. Replacing every instance in code of "removableHead" when referencing Spectres. The new code checks for "head" first, and then falls back to "removableHead" if it doesn't find it, so it shouldn't cause any issues if someone disables Northstar.Custom or uses a Spectre model that doesn't have this change

Titanfall.2.2024-11-30.10-21-29.mp4

-cl_spectre.nut was taken from englishclient_mp_common.vpk
-_ai_spectre.gnut was taken from englishclient_sp_timeshift_spoke02.vpk ( but it should be in any sp vpk )

I'd also like to note that Stalkers technically should have this issue as well, but we can't execute them so it doesn't really matter

[ASpoonPlaysGames]

Would it not be simpler to make our execution code fall back on removeableHead if head isn't found? (And thus not need the rest of the changes)

[NachosChipeados]

Would it not be simpler to make our execution code fall back on removeableHead if head isn't found? (And thus not need the rest of the changes)

Already thought about that, but i couldn't think of a good way to do it

[ASpoonPlaysGames]

Potentially replace FORCE1P_PILOT_1P_HIDDEN_BODYGROUP with an array where we iterate over it and hide any bodygroups that we find?

[NachosChipeados]

where we iterate over it and hide any bodygroups that we find?

but thats the problem, we can't just tell it to hide any bodygroups because if the npc doesn't have them, we just run into the same issue again

Titanfall.2.2024-12-01.22-32-19.mp4

Here, i got an error because grunts don't have "removableHead"

	array<string> hiddenBodygroupsArray = [ "head", "removableHead" ]

	foreach ( hiddenBodygroup in hiddenBodygroupsArray )
	{
		int bodygroupValue = 1
		if ( hiddenBodygroup == "torso" )
			bodygroupValue = 2
	
		// hide annoying bodygroup
		ownerProxy.SetBodygroup( ownerProxy.FindBodyGroup( hiddenBodygroup ), bodygroupValue )
		// don't play anim until later so we can do cleanup stuff
	}

I think there's definitely a better way to handle this entire thing, but i have no idea how else to do it

[ASpoonPlaysGames]

Copied from discord: https://discord.com/channels/920776187884732556/950322078945538058/1313222452683210825

@NachosChipeados re: #910
FindBodygroup returns -1 if the bodygroup doesnt exist

Could probably fairly easily prevent this code from crashing at all by checking the return value before trying to set the bodygroup, combined with the stuff I suggested should make a fairly robust way of doing this