Fix back stack didn't perserved when Files Activity launched by Setting storage then back case.
Due to FilesActivity set "android:documentLaunchMode="intoExisting", it will create
new task when launched from Storage Setting page.
When select FilesActivity task from recents & press back key, it will not back
to settings page.
Using startActivityForResult to set task as source task can fix task separated case.
Change-Id: I26362928261a1a9c0e485a486be493423d1fcf61
Fixes: 33117269
Test: Manual
Test: atest StorageItemPreferenceControllerTest
2 files changed