flatpak: handle end_of_lifed_with_rebase

when end_of_lifed_with_rebase is called we need to render a decision on whether to move to the replacement for the EOL flatpak or not. we do this in two ways

1. runtime/ is always auto-transitioned because we consider this implementation details that dont need surfacing to the user
2. everything else (i.e. app/) surfaces a proceed request via the existing job interface

since we are dealing with a transaction thread the implementation uses a bog standard waitcondition to implement the blocking aspect of this (i.e. the callback doesn't return until the user made a proceed decision causing the wait condition to get awoken)

BUG: 485886

Test plan

1. flatpak install com.github.Eloston.UngoogledChromium. Say no when asked if you want to use io.github.ungoogled_software.ungoogled_chromium instead
2. flatpak update --commit=087eee78436ba932c36d4e14617513ae921ccdabd15d40bdd2cf1f80515e34fe com.github.Eloston.UngoogledChromium. Say no when asked if you want to use io.github.ungoogled_software.ungoogled_chromium instead
3. plasma-discover --mode Update
4. Click the "Update" button