upsert() of an Entity with lazy relation results in null column value

Issue description

upsert() of an Entity with lazy relation results in null column value

Expected Behavior

upsert() can recognize value in lazy relation field named otherEntity.

Actual Behavior

upsert() looks for __otherEntity__ field.

Steps to reproduce

await dataSource.entityManager.upsert(
  MyEntity,
  {
    externalReference: '...',
    otherEntity: Promise.resolve(otherEntity),
  },
);

with

@Entity()
export class MyEntity {
   @Column({ unique: true })
  @Index({ unique: true })
  externalReference: string;

  @ManyToOne(() => MyOtherEntity, { lazy: true })
  @JoinColumn()
  otherEntity: Promise<MyOtherEntity>;
};

results in otherEntityId column to be empty because getLazyRelationsPromiseValue is not true thus it expects a __otherEntity__ field: https://github.com/typeorm/typeorm/blob/d184d8598c057ce8fa54815e669b567238f3a86e/src/metadata/RelationMetadata.ts#L474

My Environment

Dependency	Version
Operating System	macOS
Node.js version	21.1.0
Typescript version	5.1.3
TypeORM version	0.3.17

Additional Context

No response

Relevant Database Driver(s)

[ ] aurora-mysql
[ ] aurora-postgres
[ ] better-sqlite3
[ ] cockroachdb
[ ] cordova
[ ] expo
[ ] mongodb
[ ] mysql
[ ] nativescript
[ ] oracle
[X] postgres
[ ] react-native
[ ] sap
[ ] spanner
[ ] sqlite
[ ] sqlite-abstract
[ ] sqljs
[ ] sqlserver

Are you willing to resolve this issue by submitting a Pull Request?

Yes, I have the time, but I don't know how to start. I would need guidance.

typeorm / typeorm

upsert() of an Entity with lazy relation results in null column value #10530