ApexManager: Allow duplicating VNDK APEX package names

Don't throw when the duplicating APEX names are VNDK.

Explicitly allow duplicating builtin packages if they are VNDK APEX.
For example, aosp_bonito has its VNDK APEX installed in the vendor
partition and GSI installed its VNDK APEX in system partition.
When booting with GSI as the system image, there would be two APEXes
with the same name "com.android.vndk.v30", and only one is activated
by apexd:

- (inactive) /vendor/apex/com.android.vndk.current.on_vendor.apex
-   (active) /system/apex/com.android.vndk.current.apex

Bug: 160611268
Test: Flash aosp_bonito / vendor.img + aosp_arm64 / system.img and boot
  to home screen
Test: atest CtsStagedInstallHostTestCases
Test: atest FrameworksServicesTests:PackageParserTest
Test: atest FrameworksServicesTests:ApexManagerTest
Test: adb shell dumpsys package
Test: | com.android.vndk.current.apex is active
Test: | com.android.vndk.current.on_vendor.apex is inactive
Change-Id: I9f01ba075f26d22aa5101dc3da69d53c5a8b6202