[BUG] Nested controllers no longer produce correct routes
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## Information

- **Version:** 7.13.0
- Packages: `@tsed/common`

I use nested controllers. In version `v6.133.1` tsed would correctly combine the paths in the `@Controller` decorator to form the full routes in the OpenAPI Specification. In version `v7.13.0`, however, the paths are no longer correctly combined.

## Example
I have the following controllers:
```ts
@Controller({
    path: '/domain/:contextID',
    children: [
        CommentController,
    ],
})
export class DomainController {}
```

```ts
@Controller({
    path: '/comments',
    children: [FlaggedCommentController],
})
export class CommentController {}
```

```ts
@Controller('')
export class FlaggedCommentController {

    @Get('/flag')
    async list() {}

    @Post('/:commentID/flag')
    async create() {}
}
```

In version `v6.133.1` this would result in the routes `/domain/{contextID}/comments/flag` and `/domain/{contextID}/comments/{commentID}/flag` for the `FlaggedCommentController`. However, in version `v7.13.0` I get the routes `/flag` and `/{commentID}/flag`.

## Acceptance criteria

When the routes `/domain/{contextID}/comments/flag` and `/domain/{contextID}/comments/{commentID}/flag` are generated for the `FlaggedCommentController`.
