remove obsolete code after upgrading to bson4

[Uzlopak]

There was a remark to remove a code block if we upgraded to bson4....

[AbdelrahmanHafez]

Good catch, thanks 👍

[vkarpov15]

I took a closer look and confirmed the original issue no longer happens in Mongoose 6. Below script errors out with BSONTypeError: Unrecognized or invalid _bsontype: ObjectID22

'use strict';
  
const mongoose = require('mongoose');

mongoose.set('debug', true);
mongoose.set('strictQuery', false);

const { Schema } = mongoose;

run().catch(err => console.log(err));

async function run() {
  await mongoose.connect('mongodb://localhost:27017/test');

  await mongoose.connection.dropDatabase();

  const Test = mongoose.model('Test', Schema({ name: String }));

  await Test.create({ name: 'foo' });
  const res = await Test.findOne({ _bsontype: 'ObjectID22' });
  console.log(res);
}