Revert "Replace ResourcePath with ResPath (#15308)" (#15551)

Content.Server/Procedural/DungeonAtlasTemplateComponent.cs

@@ -9,5 +9,5 @@ namespace Content.Server.Procedural;
 public sealed class DungeonAtlasTemplateComponent : Component
 {
     [DataField("path", required: true)]
-    public ResPath Path;
+    public ResourcePath? Path;
 }

Content.Server/Procedural/DungeonSystem.cs

@@ -145,7 +145,7 @@ public sealed partial class DungeonSystem : EntitySystem
         while (query.MoveNext(out var uid, out comp))
         {
             // Exists
-            if (comp.Path.Equals(proto.AtlasPath))
+            if (comp.Path?.Equals(proto.AtlasPath) == true)
                 return Transform(uid).MapID;
         }