Fix responses context when no response (#1754)

engine/apps/webhooks/models/webhook.py

@@ -274,4 +274,5 @@ class WebhookResponse(models.Model):
     content = models.TextField(null=True, default=None)
 
     def json(self):
-        return json.loads(self.content)
+        if self.content:
+            return json.loads(self.content)

engine/apps/webhooks/tests/test_trigger_webhook.py

@@ -297,6 +297,7 @@ def test_execute_webhook_using_responses_data(
             public_primary_key="response-1",
         ),
         trigger_type=Webhook.TRIGGER_FIRING,
+        status_code=200,
         content=json.dumps({"id": "third-party-id"}),
     )
     make_webhook_response(
@@ -306,8 +307,20 @@ def test_execute_webhook_using_responses_data(
             public_primary_key="response-2",
         ),
         trigger_type=Webhook.TRIGGER_ACKNOWLEDGE,
+        status_code=200,
         content=json.dumps({"id": "third-party-id", "status": "updated"}),
     )
+    # webhook wasn't executed because of some error, there is no content or status_code
+    make_webhook_response(
+        alert_group=alert_group,
+        webhook=make_custom_webhook(
+            organization=organization,
+            public_primary_key="response-3",
+        ),
+        trigger_type=Webhook.TRIGGER_SILENCE,
+        content=None,
+        status_code=None,
+    )
 
     mock_response = MockResponse()
     with patch("apps.webhooks.utils.socket.gethostbyname") as mock_gethostbyname: