[BUG] Serialization with Generic Pagination. Items are not serialized correctly. 
### Describe the bug

Using serialization with a generic pagination does not serialize the items correctly. See code snippet.

### To Reproduce

See code snippet

### Expected behavior

Items within the items array should be serialized correctly, e.g. `{"items":[{"id":"64f05e452ecc156cff3b58f4","name":"Test"}],"totalCount":1}`

### Code snippets

```TypeScript
import { Controller } from "@tsed/di";
import { Model, ObjectID } from "@tsed/mongoose";
import { Get, Ignore, Property, Returns } from "@tsed/schema";
import { CollectionOf, Generics, Required } from "@tsed/schema";

@Generics("T")
export class Pagination<T> {
  @CollectionOf("T")
  @Required()
  items: T[];

  @Required()
  totalCount: number;

  constructor(partial: Partial<Pagination<T>>) {
    Object.assign(this, partial);
  }
}

@Model()
class TestEntity {
  @ObjectID("id")
  public _id: string;

  @Property()
  name: string;

  @Property()
  @Ignore()
  secret: string;
}

@Controller("/hello-world")
export class HelloWorldController {
  constructor() {}

  @Get("/")
  @Returns(200, Pagination).Of(TestEntity)
  get() {
    const item = new TestEntity();
    item._id = "64f05e452ecc156cff3b58f4";
    item.name = "Test";
    item.secret = "top";

    const pagination = new Pagination({ items: [item], totalCount: 1 });

    return pagination;
    // expected: {"items":[{"id":"64f05e452ecc156cff3b58f4","name":"Test"}],"totalCount":1}
    // actual: {"items":[{"_id":"64f05e452ecc156cff3b58f4","name":"Test","secret":"top"}],"totalCount":1}
  }
}
```


### Repository URL example

_No response_

### OS

macOS

### Node version

v18.16.0

### Library version

v7.37.0

### Additional context

Does work as expected in v7.35.1