Add logic to start FACTORY_RESET only after REBOOT completed

In case a package crashes very frequently, the escalation level 5 triggers before the level 4 is finished in RescueParty.
Hence the device could get FACTORY_RESET even before we try WARM_REBOOT
for rescue. Using the system property PROP_ATTEMPTING_REBOOT ensuring that factory reset level is executed only after reboot has taken place.

Bug: b/257269267
Test: atest RescuePartyTest

Change-Id: I64dfd0d93d5b17fcfe3cf1cb110e27e926b1052d