_op: delete returning on after save object result

New Issue Checklist

• [ x ] I am not disclosing a vulnerability.
• [ x ] I am not just asking a question.
• [ x ] I have searched through existing issues.
• [ x ] I can reproduce the issue with the latest version of Parse Server.

Issue Description

When we save an object on parse and delete a property, it is returning in the API { __op: 'Delete' }
We manipulate the object on AfterSave and print it before returning, and it doesn't appear these values.
It looks like it is added after the afterSave.

Steps to reproduce

Delete a value on a property field:

    if (!helper.isNullOrUndefined(skippedAt) && dirtyKeys.includes("skippedAt")) {
        eventOccurrence.set("skippedAt", new Date(skippedAt));
    } else {
        eventOccurrence.set('skippedAt', { __op: 'Delete' });
    }

Actual Outcome

"skippedAt":{"__op":"Delete"},
"rescheduledTo":{"__op":"Delete"},
"deletedAt":{"__op":"Delete"}

Expected Outcome

Don't return these information, because it broke the Model serialization in the apps front end

Environment

Parse server Version 5.4.0 with MongoDB 5

Server

• Parse Server version: 5.40
• Operating system: Linux Ubuntu
• Local or remote host: Google Cloud

Database

• System (MongoDB or Postgres): Mongo
• Database version: 5.0.14
• Local or remote host (MongoDB Atlas, mLab, AWS, Azure, Google Cloud, etc): MongoDB Atlas

Logs

Start by tracing the AfterSave lifecycle and the object serialization path for save operations that use the { __op: 'Delete' } marker. Reproduce the reported response with the provided skippedAt example, then verify that deleted fields are absent from the returned API object without changing the AfterSave-visible object.