Fix specs and syntax

- Add changlog

app/models/project_services/alerts_service.rb

@@ -81,7 +81,7 @@ class AlertsService < Service
   end
 
   def update_http_integration
-    return unless type == 'AlertsService'
+    return unless project_id && type == 'AlertsService'
 
     AlertManagement::SyncAlertServiceDataService # rubocop: disable CodeReuse/ServiceClass
       .new(self)

app/services/alert_management/sync_alert_service_data_service.rb

@@ -2,7 +2,6 @@
 
 module AlertManagement
   class SyncAlertServiceDataService
-
     # @param alert_service [AlertsService]
     def initialize(alert_service)
       @alert_service = alert_service

changelogs/unreleased/255519-migrate-existing-generic-alert-endpoints-to-http-integrations-form.yml

+---
+title: Migrate Alert Service to HTTP Integrations model
+merge_request: 46188
+author:
+type: added