Fix not calling App::finish and App::cleanup in `ScheduleRunnerPl…

…ugin` (#9054)

This pull request is mutually exclusive with #9066.

# Objective

Complete the initialization of the plugin in `ScheduleRunnerPlugin`.

## Solution

Wait for asynchronous tasks to complete, then `App::finish` and
`App::cleanup` in the runner function.

crates/bevy_app/src/schedule_runner.rs

@@ -71,6 +71,13 @@ impl Plugin for ScheduleRunnerPlugin {
  fn build(&self, app: &mut App) {
  let run_mode = self.run_mode;
  app.set_runner(move |mut app: App| {
+ while !app.ready() {
+ #[cfg(not(target_arch = "wasm32"))]
+ bevy_tasks::tick_global_task_pools_on_main_thread();
+ }
+ app.finish();
+ app.cleanup();
+
  let mut app_exit_event_reader = ManualEventReader::<AppExit>::default();
  match run_mode {
  RunMode::Once => {