[CAL-4515] Integration tests for no-show webhooks

[zomars]

Following #16727

Requirements

We need to test the following scenarios:

• When scheduling a webhook expect the correct Tasker job to be created
• On another test, make sure the task payload is correct
• Given a Task, ensure the task handler runs properly with the correct payload
• Make sure a Task is deleted when the webhook is deleted

_{From SyncLinear.com | CAL-4515}

[zomars]

cc @CarinaWolli for assignment 🙏

[CarinaWolli]

@Udit-takkar can you work on that? not urgent but we should add these tests 🙏