Package whitelist for hiddenapi checks.

Some packages in the system image are not built against the SDK, so
enforcing hiddenapi checks for these will break them. Add a whitelist
for such packages.

For now, just add the contacts provider to the whitelist. The list will be
further populated later.

Test: Added test app package name to whitelist to verify.

Bug: 73244707
Change-Id: I94746b7f12dd9371d5068bb235eb853f63ee4d97