重构toast消息的两个订阅

我有以下代码,我试图重构只有一个订阅没有成功。

this.emailsService.askOptionOne(email).pipe(
  takeUntil(this.ngUnsubscribe)
).subscribe(
  () => {
    this.isBusy = false;

    assistanceForm.reset();
    this.router.navigate(['/']);

    this.translateService.get('The request has been sent.').subscribe((message: string) => {
      this.toastrService.success(message);
    });
  },
  (error: any) => {
    this.isBusy = false;

    this.translateService.get(error).subscribe((message: string) => {
      this.toastrService.error(message);
    });
  }
);

我目前所做的努力:

this.emailsService.askOptionOne(email).pipe(
  switchMap(() => of('The request has been sent.')),
  catchError((error: any) => of(error)),
  switchMap((message: any) => this.translateService.get(message)),
  takeUntil(this.ngUnsubscribe)
).subscribe(
  (message: any) => {
    this.isBusy = false;

    assistanceForm.reset();
    this.router.navigate(['/']);

    this.toastrService.success(message);
  },
  (error: any) => {
    this.isBusy = false;

    this.toastrService.error(error)
  }
);

这个版本的问题是结果永远不会出错。

有重构这段代码的线索吗?

谢谢你的帮助。