fix(badge): Update realm before updating the badge

[SystemKeeper]

How to reproduce:

• Write 2 messages and see that your badge is increased by 2
• Read the messages on web, to mark them as unread
• Notice that (sometimes) the badge is not decreased by 2 again, but sometimes only by 1 or not at all

After we removed the notifications, we also update the badgenumber:

talk-ios/NextcloudTalk/NCNotificationController.m

Lines 308 to 319 in a06a909

	[_notificationCenter getDeliveredNotificationsWithCompletionHandler:^(NSArray<UNNotification *> * _Nonnull notifications) {
	for (UNNotification *notification in notifications) {
	if (expired) {
	dispatch_group_leave(notificationsGroup);
	return;
	}
	removeNotification(notification.request, NO);
	}
	[self updateAppIconBadgeNumber];
	dispatch_group_leave(notificationsGroup);
	}];

Since this is wrapped in a dispatch, it is possible that realm was not yet fully updated on the other thread:

talk-ios/NextcloudTalk/NCNotificationController.m

Lines 229 to 231 in a06a909

	dispatch_async(dispatch_get_main_queue(), ^{
	[UIApplication sharedApplication].applicationIconBadgeNumber = [[NCDatabaseManager sharedInstance] numberOfUnreadNotifications];
	});

Resulting in a wrong badge count.