chore(): remove method of() and added EMPTY constant

Author: Tony133

src/app/homepage/newsletter/services/newsletter.service.ts

@@ -1,6 +1,6 @@
 import { HttpClient } from '@angular/common/http';
 import { Injectable } from '@angular/core';
-import { of } from 'rxjs';
+import { EMPTY } from 'rxjs';
 import { catchError } from 'rxjs/operators';
 
 @Injectable({ providedIn: 'root' })
@@ -12,7 +12,7 @@ export class NewsletterService {
       'https://z93f42xq2l.execute-api.us-east-2.amazonaws.com/Stage/newsletter?token=db1f899025b5a59a76b6b34b2a013893';
     return this.httpClient
       .post(newsletterUrl, { email })
-      .pipe(catchError(() => of()))
+      .pipe(catchError(() => EMPTY ))
       .toPromise();
   }
 }