The names of entity properties are not converted to column names when used in the qb.onConflict method

[mrmlnc]

Describe the bug

The names of entity properties are not converted to column names when used in the qb.onConflict method.

At the same time, TS types indicate that I can use entity field names.

await orm.em.createQueryBuilder(UserEntity)
    .insert([{ externalId: '1', organization: 1 }, { externalId: '2', organization: 1 }])
    // Entity field – column name
    // externalId – external_id
    // organization – organization_id
    // 
    // TS types: externalId, id, organization 
    .onConflict(['externalId', 'organization'])
    .ignore()
    .execute();

Stack trace

insert into "user" ("external_id", "organization_id") values ('1', 1), ('2', 1)
on conflict ("externalId", "organization") do nothing returning "id" - column "externalId" does not exist

To Reproduce

📖 I have a repository that makes it easy to reproduce the problem:
https://github.com/mrmlnc/mikro-orm-onConflict-mapper-issue

Steps to reproduce the behavior:

1. git clone https://github.com/mrmlnc/mikro-orm-onConflict-mapper-issue
2. npm ci
3. npm start

Expected behavior

I expect to be able to use entity field names in this method.

Additional context

It looks like the bug is here:

mikro-orm/packages/knex/src/query/QueryBuilderHelper.ts

Line 404 in 2ab7d7e

const sub = item.fields.length > 0 ? qb.onConflict(item.fields) : qb.onConflict();

The mapper is not used here when passing fields to QB. In other methods it is used.

Also the problem can be reproduced in V6.

Versions

Dependency	Version
node	16.16.0
typescript	4.7.4
mikro-orm	5.7.12
your-driver	postgresql