fix: update isValid comment and remove unused showDeleteInfo$

Author: escire-dspace

src/app/shared/subscriptions/subscription-modal/subscription-modal.component.ts

@@ -96,11 +96,6 @@ export class SubscriptionModalComponent implements OnInit {
    */
   public processing$ = new BehaviorSubject<boolean>(false);
 
-  /**
-   * If true, show a message explaining how to delete a subscription
-   */
-  public showDeleteInfo$ = new BehaviorSubject<boolean>(false);
-
   /**
    * Reactive form group that will be used to add/edit subscriptions
    */
@@ -122,7 +117,7 @@ export class SubscriptionModalComponent implements OnInit {
   frequencyDefaultValues = ['D', 'W', 'M'];
 
   /**
-   * True if form status has changed and at least one frequency is checked
+    * True if form status has changed and submit action is valid
    */
   isValid = false;
   /**