Use schema collection instead of adaptive collection for all schema operations.

src/Adapters/Storage/Mongo/MongoCollection.js

@@ -76,17 +76,6 @@ export default class MongoCollection {
     return this._mongoCollection.updateMany(query, update);
   }
 
-  // Atomically find and delete an object based on query.
-  // The result is the promise with an object that was in the database before deleting.
-  // Postgres Note: Translates directly to `DELETE * FROM ... RETURNING *`, which will return data after delete is done.
-  findOneAndDelete(query) {
-    // arguments: query, sort
-    return this._mongoCollection.findAndRemove(query, []).then(document => {
-      // Value is the object where mongo returns multiple fields.
-      return document.value;
-    });
-  }
-
   deleteOne(query) {
     return this._mongoCollection.deleteOne(query);
   }