Auto selected sub should never be actual default sub

Not using featureflag because this change revert to the behavior prior to ag/19933665, which accidentally made auto selected sub to be the actual sub id, instead of max_int. This is an issue if the device is uncapable of validation before switching.

Fix: 303941269
Test: voice call + data browsing
Change-Id: Ib331554e5fa31136f375e6532269610a717f7ce8