The API changed from addCrossProfileCalendarPackage to
setCrossProfileCalendarPackages recently due to our decision
in b/121179845. Also added test for the case when
the whitelist is set to null.
Bug: 121179845
Test: make ROBOTEST_FILTER=CrossProfileCalendarPreferenceControllerTest -j40 RunSettingsRoboTests
Change-Id: I66b92aba6d26334e48207275b2d8981203598e15