Fix a missing migration

This was breaking old saves

macrovision.js

@@ -6248,12 +6248,18 @@ const migrationDefs = [
         data.entities.forEach((entity) => {
             entity.flipped = false;
         });
-    }
+    },
     /*
     Migration: 5 -> 6
 
     Entities can now have custom attributes 
     */
+
+    (data) => {
+        data.entities.forEach((entity) => {
+            entity.views = {};
+        });
+    }
 ];
 
 function migrateScene(data) {