Carry over everything except the character's position when going up
stairs, so that eg the character doesn't lose everything they picked up
and instantly heal to full when going up a level.
Change-Id: I08513578a72f2410a363bbadbb273d95826a3f1b
Reviewed-on: https://cl.tvl.fyi/c/depot/+/3766
Reviewed-by: grfn <grfn@gws.fyi>
Tested-by: BuildkiteCI