Change the return of getCurrentPackageName to nullable.

getCurrentPackageName returns the calling package name. In some case,
there may be no known package for given binder calling uid. Then, NPE
can be thrown by attempting to read null array.
Therefore, changed to nullable for getCurrentPackageName function,
and return null if there is no known package name for calling uid

Bug: 318525350
Test: atest PhoneInterfaceManagerTest
Change-Id: I1c9be056aae998abfe3ee4ed641c2cd5bfaaa9c7
2 files changed