Clean up polymorphsystem (#14297)

Content.Server/Polymorph/Systems/PolymorphSystem.Map.cs

@@ -0,0 +1,41 @@
+using Content.Shared.GameTicking;
+
+namespace Content.Server.Polymorph.Systems
+{
+    public sealed partial class PolymorphSystem
+    {
+        public EntityUid? PausedMap { get; private set; }
+
+        /// <summary>
+        /// Used to subscribe to the round restart event
+        /// </summary>
+        private void InitializeMap()
+        {
+            SubscribeLocalEvent<RoundRestartCleanupEvent>(OnRoundRestart);
+        }
+
+        private void OnRoundRestart(RoundRestartCleanupEvent _)
+        {
+            if (PausedMap == null || !Exists(PausedMap))
+                return;
+
+            EntityManager.DeleteEntity(PausedMap.Value);
+        }
+
+        /// <summary>
+        /// Used internally to ensure a paused map that is
+        /// stores polymorphed entities.
+        /// </summary>
+        private void EnsurePausesdMap()
+        {
+            if (PausedMap != null && Exists(PausedMap))
+                return;
+
+            var newmap = _mapManager.CreateMap();
+            _mapManager.SetMapPaused(newmap, true);
+            PausedMap = _mapManager.GetMapEntityId(newmap);
+
+            Dirty(PausedMap.Value);
+        }
+    }
+}