Does NdkCxxPlatforms need to statically define versions?

Created by: ZacSweers

This is a recurring issue for us, as we have to manually update every time there's a new major NDK release and it blocks local development until we update buck or go through the tedium of downgrading the NDK version on the system. Can we make the number matching accept any upper bound with the caveat of being unsupported/YMMV?

CC @kageiit