Ensure hibernation exemption toggle uses pre-S flag

For dogfood, we want hibernation to target apps that target pre-S. This
was done on the PermissionController side but the toggle in Settings
did not visually reflect this policy, confusing dogfood/teamfood
participants.

This updates the default toggle position to consider whether the pre-S
flag is on and then default to the "on" position for apps targeting
pre-S if the flag was on for the device.

Bug: 189260947
Test: atest HibernationSwitchPreferenceControllerTest
Test: manual
Change-Id: I9cd16e82e1eee4589cb17a356b6bf2e3297a8dd2