Function resolve_pm_deps 

pub async fn resolve_pm_deps(
    resolver: &ResourceResolver,
    pm_timer_assist_resource: Option<Resource<PmTimerAssistHandleKind>>,
) -> Result<ResolvedPmDeps, ResolvePmError>

Resolve the common PM dependencies (power request handler and optional PM timer assist) that are shared by both the Hyper-V and PIIX4 PM resolvers.

This performs the async resolution work up-front so that the resulting ResolvedPmDeps can be passed to PowerManagementDevice::new synchronously.