Akka.Cluster.Hosting: ShardOptions.PassivateIdleEntityAfter overwrites custom akka.cluster.sharding.passivate-idle-entity-after setting in HOCON

[Aaronontheweb]

Version Information
Version of Akka.NET? v1.5.6
Which Akka.NET Modules? Akka.Cluster.Hosting

Describe the bug

Not 100% if this is a bug or not yet (going off an end-user's report), but if I set

akka.cluster.sharding.passivate-idle-entity-after = 24h #24 hours

In a separate .hocon file added via the AddHoconFile method (with prepending et al done correctly), but if I start any ShardRegion using the default ShardOptions (without specifying ShardOptions.PassivateIdleEntityAfter) I get the following logs:

This indicates that we're still using the default 2 minutes setting, and I believe that's because of our default value for ShardOptions here:

Akka.Hosting/src/Akka.Cluster.Hosting/AkkaClusterHostingExtensions.cs

Line 288 in 9e08da2

public TimeSpan? PassivateIdleEntityAfter { get; set; } = TimeSpan.FromMinutes(2);

To Reproduce

1. Create ActorSystem with akka.cluster.sharding.passivate-idle-entity-after = 24h
2. Start ShardRegion using Akka.Hosting;
3. Check to see if the passivation timeout is 2 minutes instead of 24 hours.

Additional context

We should probably make null the default value here so that way the HOCON values will be used if not user-supplied value is defined.