init: 'user root' check use vendor API

This changes user root to use the year date format
that vendor API uses.

Previously this still applied to V devices, which switched
to using API level 202404 after 35.

They recommend the year/date form, and there is no
constant for this.

Bug: 340953047
Test: service_test
Change-Id: I5ba8d1251c877a785e41f0cfcc35d7cb0776f8c7