Fixes lua function SS13.wait. (#85427)

## About The Pull Request
See title. It's broken because it's not resuming the proper yielded
coroutine, it's getting the global next yield index.

## Why It's Good For The Game
Fixes SS13.wait breaking if called more than once.

## Changelog
🆑
fix: Fixes SS13.wait not working when called multiple times before it
finishes waiting.
/🆑

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

lua/timer.lua

@@ -60,8 +60,9 @@ __Timer_timer_process = function(seconds_per_tick)
 end
 
 function Timer.wait(time)
+	local yieldIndex = _exec.next_yield_index
 	__add_internal_timer(function()
-		SSlua:queue_resume(state.state, _exec.next_yield_index)
+		SSlua:queue_resume(state.state, yieldIndex)
 	end, time * 10, false)
 	coroutine.yield()
 end