Splits the slowdown between the space helmet and the space suit (#85704)

## About The Pull Request
As the title says. Instead of space suits providing all of the slowdown,
it provides half of the slowdown and the other half is given to the
space helmet as slowdown too.

Closes #85702

## Why It's Good For The Game
By splitting the slowdown cost between the two components that make a
traditional space suit, players will no longer gain pepperspray immunity
with no downside.

This also does provide the benefit of moving a bit faster if you aren't
wearing a bulky space suit helmet and I think it does just add to the
immersion a lot more if it were the two components of the space suit
that slowed you down together rather than one or the other.

## Changelog
🆑
balance: Space suits no longer provide all of the slowdown when wearing
space gear. Helmets now share the burden and you can now move faster
when wearing only a space suit. Helmets now provide a bit of slowdown
when worn alone as a result.
/🆑

---------

Co-authored-by: Watermelon914 <3052169-Watermelon914@users.noreply.gitlab.com>

code/modules/shuttle/emergency.dm

@@ -755,12 +755,13 @@
 	name = "emergency space helmet"
 	icon_state = "syndicate-helm-orange"
 	inhand_icon_state = "syndicate-helm-orange"
+	slowdown = 1.5
 
 /obj/item/clothing/suit/space/orange
 	name = "emergency space suit"
 	icon_state = "syndicate-orange"
 	inhand_icon_state = "syndicate-orange"
-	slowdown = 3
+	slowdown = 1.5
 
 /obj/item/pickaxe/emergency
 	name = "emergency disembarkation tool"