fix(alerts): Fix TypeError in Alert Serializer (#57689)

Fix SENTRY-167V

src/sentry/api/serializers/models/alert_rule.py

@@ -110,7 +110,9 @@ class AlertRuleSerializer(Serializer):
                 "triggers", []
             )
             for action in serialized.get("actions", []):
-                install = sentry_app_installations_by_sentry_app_id.get(str(action["sentryAppId"]))
+                install = sentry_app_installations_by_sentry_app_id.get(
+                    str(action.get("sentryAppId"))
+                )
                 if install:
                     action["_sentry_app_component"] = install.get("sentry_app_component")
                     action["_sentry_app_installation"] = install.get("sentry_app_installation")