Fix the exception thrown when API called bug

The isEnabledCredentialProviderService is
currently throwing an NPE when called. This
updates the logic of that method to be
aligned with the rest of the class and fix
the error.

Test: AndroidVault custom logic
Bug: 307592997
Change-Id: If0091cd68f8c773d64acf37058893117555d4d73
2 files changed