Add Notification Filters for Seen and Priority

- Introduced new optional fields in the SearchForm for filtering notifications by 'seen' status and 'priority', enhancing the flexibility of notification retrieval.
- Updated the GetNotifications method in the notification service to accommodate the new filters, ensuring they are included in the query parameters.
- Enhanced the notification client to support the new filters in API requests, improving the overall functionality of the notification system.
- Updated API documentation with Swagger comments to reflect the new query parameters, ensuring clarity for API consumers.

internal/notification/form.go

@@ -26,6 +26,8 @@ type SearchForm struct {
 	EventType string `query:"event_type" valid:"optional"`
 	Type      string `query:"type" valid:"optional"`
 	Recipient string `query:"recipient" valid:"optional"`
+	Seen      *bool  `query:"seen" valid:"optional"`
+	Priority  string `query:"priority" valid:"optional"`
 }
 
 type NotificationListResponse struct {