Reduce flickers when launching Storage Settings

This change remove unnecessary UI dpdate of
StorageItemPreferenceController.

- For StorageItemPreferenceController:
  Remove UI update at #displayPreference since onLoadFinished will update.
  Don't update order at #setVolume since onLoadFinished will update.

- StorageDashboardFragment & StorageCategoryFragment update
  StorageItemPreferenceController only when both StorageInfo
  and StorageResult are loaded.

Bug: 185547228
Test: atest com.android.settings.deviceinfo
      atest com.android.settings.deviceinfo.storage
      make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.deviceinfo
      make RunSettingsRoboTests -j ROBOTEST_FILTER=com.android.settings.deviceinfo.storage
      manual visual
      Click each file category to count files size is the same as
      displayed in Storage Settings.
      manual visual
Change-Id: Id449003827a3e340e7a90f706152100b5568f834