use_vndk_as_stable APEX shouldn't include VNDK lib

Even though a vendor APEX sets use_vndk_as_stable:true it was possible
to include a VNDK lib by directly depending on it with
native_shared_libs.

But it's contradictory to have a VNDK lib while declaring not to include
VNDK libs. It was missing since pruning dependencies on VNDK libs was
done only for transitive deps.

Added a check to reject this.

Bug: 216847402
Test: m nothing(running soong tests)
Change-Id: I8d79a434b1bfe8e563cf8968fa76830b0e582f66