Some shutdown crash fixes, reverted a whitespace, and added some basic unit tests for time additions

Signed-off-by: kberg-amzn <karlberg@amazon.com>

Gems/Multiplayer/Code/Source/Components/MultiplayerComponentRegistry.cpp

@@ -57,4 +57,9 @@ namespace Multiplayer
         }
         return nullComponentData;
     }
+
+    void MultiplayerComponentRegistry::Reset()
+    {
+        m_componentData.clear();
+    }
 }

Gems/Multiplayer/Code/Source/MultiplayerSystemComponent.cpp

@@ -199,6 +199,8 @@ namespace Multiplayer
         AZ::Interface<INetworking>::Get()->DestroyNetworkInterface(AZ::Name(MpNetworkInterfaceName));
         AzFramework::SessionNotificationBus::Handler::BusDisconnect();
         AZ::TickBus::Handler::BusDisconnect();
+
+        m_networkEntityManager.Reset();
     }
 
     bool MultiplayerSystemComponent::StartHosting(uint16_t port, bool isDedicated)

Gems/Multiplayer/Code/Source/NetworkEntity/NetworkEntityManager.cpp

@@ -300,6 +300,21 @@ namespace Multiplayer
         }
     }
 
+    void NetworkEntityManager::Reset()
+    {
+        m_multiplayerComponentRegistry.Reset();
+        m_removeList.clear();
+        m_entityDomain = nullptr;
+        m_updateEntityDomainEvent.RemoveFromQueue();
+        m_ownedEntities.clear();
+        m_entityExitDomainEvent.DisconnectAllHandlers();
+        m_onEntityMarkedDirty.DisconnectAllHandlers();
+        m_onEntityNotifyChanges.DisconnectAllHandlers();
+        m_controllersActivatedEvent.DisconnectAllHandlers();
+        m_controllersDeactivatedEvent.DisconnectAllHandlers();
+        m_localDeferredRpcMessages.clear();
+    }
+
     void NetworkEntityManager::RemoveEntities()
     {
         AZStd::vector<NetEntityId> removeList;

Gems/Multiplayer/Code/Source/NetworkEntity/NetworkEntityManager.h

@@ -92,6 +92,9 @@ namespace Multiplayer
         void OnRootSpawnableReleased(uint32_t generation) override;
         //! @}
 
+        //! Used to release all memory prior to shutdown.
+        void Reset();
+
     private:
         void RemoveEntities();
         NetEntityId NextId();