Fail staged session if apexd session is in ROLLBACK_IN_PROGRESS state

This covers a (very unlikely) scenario, in which device was rebooted
during apexd rollback, and apexd wasn't able to resume rollback after
the reboot.

For a tiny bit more context see: aosp/912794

Bug: 123622800
Test: none
Change-Id: Idbb142dce2dbc85b818ba42e93ab107e4955301d