Function collect_all_timers_dbus 

pub async fn collect_all_timers_dbus(
    connection: &Connection,
    config: &Config,
) -> Result<SystemdUnitStats>

Collect all timer stats via D-Bus and return them ready to merge into unit stats.

Used when unit stats were collected via varlink (which doesn’t yet expose timer properties) so that timers.*, timer_persistent_units, and timer_remain_after_elapse match the D-Bus output.