Use ro.product.vendor.device to determine if running on Cuttlefish

Similar reasoning as aosp/2255456. ro.product.device could be overridden
by GSI if system.img was replaced with GSI.
Use ro.product.vendor.device, which comes from the vendor.img, to
determine the "device" type.

Bug: 243116800
Test: adb-remount-test on cuttlefish
Change-Id: Ib4a956047ef46d8e4837b27334f8d58162d4fa2a