DontDestroyWithOwner not honored on PlayerObjects

[JesseOlmer]

Description

When a client disconnects from the server the server will destroy their PlayerObject regardless of how DontDestroyWithOwner is set.

Reproduce Steps

1. Create a project with a simple Player Prefab configured.
2. Set DontDestroyWithOwner = true on player prefabs when they're spawned. e.g. Add a component with the following to the prefab:

    public override void OnNetworkSpawn()
    {
        base.OnNetworkSpawn();
        NetworkObject.DontDestroyWithOwner = true;
    }

4. Launch a client and server.
5. Close/disconnect the client.

Actual Outcome

The client prefab is destroyed on the server.

Expected Outcome

The client prefab is preserved on the server and ownership changes to the server.

Environment

• OS: macOS Monterey
• Unity Version: 2022.1.3f1
• Netcode Version: 1.0.0
• Netcode Commit: fddb7cd920e1db9e49d44846d7121e38f59bd137

Additional Context

NetworkManager.OnClientDisconnectFromServer doesn't check the field before destroying the PlayerObject.

[ashwinimurt]

Backlog: MTT-4458

[NoelStephensUnity]

This issue was resolved in #2225 and will be in the next update!