Update based on feedback. Adding event to MPSystemComponent for receiving a server acceptance packet. The editor system component subscribes to this event and tells the server we're ready for entity updates

Signed-off-by: Gene Walters <genewalt@amazon.com>

Gems/Multiplayer/Code/Include/Multiplayer/IMultiplayer.h

@@ -44,6 +44,7 @@ namespace Multiplayer
 
     using ClientDisconnectedEvent = AZ::Event<>;
     using ConnectionAcquiredEvent = AZ::Event<MultiplayerAgentDatum>;
+    using ServerAcceptanceReceivedEvent = AZ::Event<>;
     using SessionInitEvent = AZ::Event<AzNetworking::INetworkInterface*>;
     using SessionShutdownEvent = AZ::Event<AzNetworking::INetworkInterface*>;
 
@@ -102,6 +103,10 @@ namespace Multiplayer
         //! @param handler The ConnectionAcquiredEvent Handler to add
         virtual void AddConnectionAcquiredHandler(ConnectionAcquiredEvent::Handler& handler) = 0;
 
+        //! Adds a ServerAcceptanceReceived Handler which is invoked when the client receives the accept packet from the server.
+        //! @param handler The ServerAcceptanceReceived Handler to add
+        virtual void AddServerAcceptanceReceivedHandler(ServerAcceptanceReceivedEvent::Handler& handler) = 0;
+
         //! Adds a SessionInitEvent Handler which is invoked when a new network session starts.
         //! @param handler The SessionInitEvent Handler to add
         virtual void AddSessionInitHandler(SessionInitEvent::Handler& handler) = 0;