Using Schema.loadClass with a class which inherits from Document will hang up any find operations.

[WolverinDEV]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the bug has not already been reported

Mongoose version

6.5.2

Node.js version

v16.13.0

MongoDB server version

docker latest (c8b57c4bf7e3)

Description

When using Schema.loadClass with an class inheriting from Document, loading such entries will stall forever.
A simple fix would be:

import { Document } from "mongoose";
import * as mongoose from "mongoose";

// For details see https://github.com/Automattic/mongoose/issues/12254
mongoose.Schema.prototype.loadClass = function(original: Function) {
    return function(this: mongoose.Schema, model: any, ...args: any[]) {
        if(model === Document) {
            /* Don't load mongoose Document class. */
            return;
        }

        return original.call(this, model, ...args);
    }
}(mongoose.Schema.prototype.loadClass);

Steps to Reproduce

const DownloadJobSchema = new mongoose.Schema();

class B extends Document {}
DownloadJobSchema.loadClass(B);

/* Create at least one entry which could be found. */
this.jobsModel.create({ someKey: "with some data" });

/* Lets find that one entry... */
console.log("Finding one entry");
this.jobsModel.findOne({}).then(() => console.log("You'll never see me!"));

Expected Behavior

findOne finding one entry in the database and return it.