Describe the bug

This is a follow-up to #6076 (sorry again for the first failed reproduction test case!)

This regression was introduced in v6.3.11 and probably linked to 55df57f (#6050).

When persisting a date inside a JSON property with the MongoDB driver, it is correctly saved as an ISODate.

When retrieving the document, the MongoDB driver returns an ISODates object (BSON date), but MikroORM hydration erases its content and prototype. The date is instead hydrated as an empty object {}.

Reproduction

Here is a test case: https://github.com/alexandre-abrioux/mikro-orm-issues/blob/iss-6078/src/example.test.ts

What driver are you using?

@mikro-orm/mongodb

MikroORM version

6.3.11

Node.js version

22.4.0

Operating system

No response

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