Fix ItemsProviderTest flakiness

Made the PickerSyncController sync delay configurable so that the
tests can set it to zero to stop sync flakiness.

Also ignored failures notifying the StorageManagerService about
cloud media provider updates

Test: atest --iterations 20 ItemsProviderTest
Bug: 214028962
Change-Id: Ifcf86862c1b5cf7c772053c6ff5ed0271928128c
Merged-In: Ifcf86862c1b5cf7c772053c6ff5ed0271928128c
(cherry picked from commit c42e1044457c931a60cb44e1c1c90e3e1f6c2ecd)
3 files changed