Fix test assumption for KeyMint+RKP integration

It's not enough to verify that the system is running KeyMint 2+. We
also need to verify that the vendor partition has RKP support.

Since VSR 13+ requires KeyMint 2+, change the test assumption so that
we don't run the test against systems that may have shipped with an
older VSR chipset (which won't support RKP).

Bug: 263844771
Test: VtsAidlKeyMintTargetTest (on old and new device)
Change-Id: Iac15f69db1152851f5a92d3929cb258b1b1a6b02