Migrate (AppsOn)ExternalStorageInfo pullers

Transition these two pullers to the new API for registering pullers.

Test: adb shell cmd stats pull-source 10053
Test: adb shell cmd stats pull-source 10057
Bug: 145565211
Change-Id: Ie1d74670018ae1f096e5e345e017e0ef3f1f153d
3 files changed