Allow ember-concurrency task `Promise<void>` in @search arg

[johanrd]

Type support for case where ember-concurrency task.perform is set as the search function.

restartableTask<unknown, (term: string) => Promise>(asyncArrowTaskFn: (term: string) => Promise): TaskForAsyncTaskFunction<unknown, (term: string) => Promise> (+4 overloads)

updateSearch = restartableTask(async (term: string) => {
  await timeout(250)
  this.router.transitionTo({ queryParams: { search: term } })
})

<PowerSelect
  @search={{this.updateSearch.perform}}
/>

[johanrd]

okay, i see the integration tests fail. Not sure how to deal with that atm, as the search action may not return anything itself, if just writing reactive state to the url.