Mover character no longer calls ProduceInput on server when the only client unpossesses it and disconnects

When a client disconnects/unpossesses a mover character, the character's Network Prediction Component will re-configure itself now that it does not have a net connection. However, this handling will not be performed if the server's only client disconnects.
FNetworkPredictionProxy::InitForNetworkRole is called from UNetworkPredictionComponent::CheckOwnerRoleChange, and this is checked each update during UNetworkPredictionComponent::PreReplication.
However, if the server no longer has any client connections, it won't call into UNetDriver::ServerReplicateActors_BuildConsiderList, where actors considered for replication will call PreReplication. Because of this, UNetworkPredictionWorldManager::ConfigureInstance is not called with the updated values for Role/bHasNetConnection, configuring it to be locally controlled.

On a server with only one client, disconnect the client. Have it unpossess its character without destroying it on the server.
Observe that the character does not receive ProduceInput calls on the server.
(See additional info URL for repro project.)

• In a multiplayer PIE session, you can use "disconnect" on a client's comment prompt to drop out of the session.
• To prevent the client's pawn from automatically being destroyed, I made a source change to APlayerController::PawnLeavingGame() by commenting out the call to GetPawn()->Destroy(). But there's probably a cleaner way to do this.