Only get target SDK version if not a VNDK client

The target SDK version is used to avoid a permission check for apps
targeting an earlier version of Android. VNDK clients don't provide a
valid op package name which causes the target SDK version check to fail.

This CL removes that target SDK version for those clients (or anyone
that fakes their VNDK op package name) and instead *always* performs the
permission check for them.

Bug: 165055606
Test: Run VNDK client and verify error is no longer printed. Also, try
popular step counter and verify it still can get step data.

Change-Id: I71c0dfa95bd4f753f6819ad46886541605a24213