refactor(streamingRequest): internal method for request functions

- TS package type inference for request functions.
- Type fix for Lua's waitFor callback.
- Lua request functions cannot return nil.

imports/requestAnimSet/client.lua

@@ -1,7 +1,7 @@
 ---Load an animation clipset. When called from a thread, it will yield until it has loaded.
 ---@param animSet string
 ---@param timeout number? Approximate milliseconds to wait for the clipset to load. Default is 1000.
----@return string? animSet
+---@return string animSet
 function lib.requestAnimSet(animSet, timeout)
     if HasAnimSetLoaded(animSet) then return animSet end
 
@@ -9,13 +9,7 @@ function lib.requestAnimSet(animSet, timeout)
         error(("expected animSet to have type 'string' (received %s)"):format(type(animSet)))
     end
 
-    RequestAnimSet(animSet)
-
-    if not coroutine.isyieldable() then return animSet end
-
-    return lib.waitFor(function()
-        if HasAnimSetLoaded(animSet) then return animSet end
-    end, ("failed to load animSet '%s'"):format(animSet), timeout)
+    return lib.streamingRequest(RequestAnimSet, HasAnimSetLoaded, 'animSet', animSet, timeout)
 end
 
 return lib.requestAnimSet