Persist dev option reboot dialog on rotation.

Use a ViewModel to store reboot dialog fragment state on rotations.

Test: locally verified rotations on few dev options that use the reboot fragment
Test: atest
com.android.settings.development.RebootConfirmationDialogFragmentTest
--iterations 25 (Passed)
Bug: 356273849
Flag: EXEMPT bug fix

Change-Id: I154170ea5fa91bcbec32af43853c5f99f8e8253d