Revert "Chore: Update infiniteScroll type (#15787)" (#15793)

This reverts commit d70ae245e6.

types/infiniteScroll.d.ts

@@ -1,6 +1,6 @@
 import { VNodeDirective } from 'vue'
 
-export interface ElInfiniteScroll extends VNodeDirective {
+export interface ElLoadingDirective extends VNodeDirective {
   name: 'infinite-scroll',
   value: Function
-}
+}