New<T> strip nullability information from entity properties

[BennoDev]

Describe the bug

The New type that gets returned from .create() methods does some funky things. It seems to strip nullability from properties.

Stack trace

No stack trace, as it's a type issue.

To Reproduce

Reproducing this is very simple using just a class and the New type.

class MyEntity {
 @Property({ nullable: true })
 nullableProperty: null | string;
}

// Type `null` is not assignable to `string`
const myNewEntityInstance: New<MyEntity> = {
 nullableProperty: null,
};

I know we would never instantiate a New<MyEntity> like above, but whether we do it via a create call or manually makes no difference for the type information.

Expected behavior

It should not modify the entity's type information. The actual type result from a .create() call is now potentially incorrect.
In the above example null is an allowed value for the MyEntity class.

Versions

Dependency	Version
node	16.13.1
typescript	4.5.5
mikro-orm	5.0.0
your-driver	postgresql

[B4nan]

Maybe we should drop the New type (we can keep it for BC and just return T from em.create()).

[BennoDev]

That would indeed fix this, and would mean that upgrading to v5 is easier, no changes should be necessary then for .create() methods