feat: Remove deprecation DEPPS1: Native MongoDB syntax in aggregation pipeline (#8362)

BREAKING CHANGE: The MongoDB aggregation pipeline requires native MongoDB syntax instead of the custom Parse Server syntax; for example pipeline stage names require a leading dollar sign like `$match` and the MongoDB document ID is referenced using `_id` instead of `objectId` (#8362)

spec/CloudCode.spec.js

@@ -2774,7 +2774,7 @@ describe('afterFind hooks', () => {
     const obj = new Parse.Object('MyObject');
     const pipeline = [
       {
-        group: { objectId: {} },
+        $group: { _id: {} },
       },
     ];
     obj