RS locks umap in MUE, meaning that multi user edit sessions cannot be persisted while RenderStream is running

[emilymalone]

Issue
When using multi user editing in Unreal, the user on the session server is normally able to exit the MUE session and persist the changes while client machines are still in the session. When a renderstream workload is running and the session server exists and persists, the umap cannot be saved until the renderstream workload has been stopped. This is an issue in that adding d3 into an existing workflow changes that workflow.

Steps
This can be tested all on one machine, running multiple instances of unreal, or on three or more distinct machines. IP addresses do not matter as long as they match.

Set up an unreal project and d3 project for renderstream

Set up Unreal for multi user editing:

On the UE host / server:

• Multi-User Editing setting > auto connect
• Multi-User Editing setting > default server name
• Multi-User Editing setting > default session name
• Multi-User Editing setting > Server Port 7000
• UDP Messaging > Unicast Endpoint (your local adapter IP) 10.1.2.2:0

On UE client:

• Multi-User Editing setting > auto connect
• Multi-User Editing setting > default server name
• Multi-User Editing setting > default session name
• UDP Messaging > Static Endpoints (server IP and server port) 10.1.2.2:7000
• Custom options in d3:
• -ConcertAutoConnect
• -ConcertSession=default session name
• -ConcertServer=default server name
• Start the MUE session in UE
• Join the session from another UE instance as a client
• Make some changes in the UE editor
• From the MUE server, exit the session and persist
• See that there are no errors
• Start the MUE session again in UE
• Start the RS workload, and see that it joins the session as '-game'
• Make some changes in the UE editor
• From the MUE server, exit the session and persist
• See that there is an error and that the map cannot save

Expected Behaviour
umap should be able to save while RS is running

Current Behaviour
umap cannot save while RS is running

[MunWolf]

This may be an Unreal issue, requires investigation.