Consolidate isApkVeritySupported to VerityUtils

As there are more customers to use isApkVeritySupported, it'd be better
for them to use something like VerityUtils instead of the service class.

Bug: 180414192
Test: m
Test: CtsAppSecurityHostTestCases:android.appsecurity.cts.ApkVerityInstallTest
Test: FrameworksServicesTests:FontCrashDetectorTest

Change-Id: I2fcc997cdd95fd6ee669d28b42232b690fd6a66e