refactor(toolkit): type source any with proper types

Genuinely type composable any usages (useStepper/useStorage/useForm/
createEventHook/useSorted/etc.) as proper generics/unknown; keep idiomatic
any-function and overload-impl signatures with comments; skipped test -> .todo.

vue/toolkit/src/composables/forms/useFieldArray/index.ts

@@ -31,7 +31,7 @@ import type {
  *
  * @since 0.0.16
  */
-export function useFieldArray<T = any>(
+export function useFieldArray<T = unknown>(
   path: MaybeRefOrGetter<string>,
   options: UseFieldArrayOptions = {},
 ): UseFieldArrayReturn<T> {