clear push notifications on open (#2336)

Author: rnystrom

Classes/Notifications/NotificationSectionController.swift

@@ -83,10 +83,13 @@ final class NotificationSectionController: ListSwiftSectionController<Notificati
             modelController.markNotificationRead(id: model.id)
         }
 
+        BadgeNotifications.clear(for: model)
+
         switch model.number {
         case .hash(let hash):
             viewController?.presentCommit(owner: model.owner, repo: model.repo, hash: hash)
         case .number(let number):
+
             let controller = IssuesViewController(
                 client: modelController.githubClient,
                 model: IssueDetailsModel(owner: model.owner, repo: model.repo, number: number),

Classes/Systems/BadgeNotifications.swift

@@ -158,4 +158,10 @@ final class BadgeNotifications {
         application.applicationIconBadgeNumber = isBadgeEnabled ? count : 0
     }
 
+    static func clear(for notification: NotificationViewModel) {
+        UNUserNotificationCenter.current().removeDeliveredNotifications(
+            withIdentifiers: [notification.identifier]
+        )
+    }
+
 }