Observability-Custom dashboards

Number of APIs: 5

1. Update an existing dashboard PATCH {{fastly_url}}/observability/dashboards/{{dashboard_id}}

2. List all custom dashboards GET {{fastly_url}}/observability/dashboards

3. Create a new dashboard POST {{fastly_url}}/observability/dashboards

4. Retrieve a dashboard by ID GET {{fastly_url}}/observability/dashboards/{{dashboard_id}}

5. Delete an existing dashboard DELETE {{fastly_url}}/observability/dashboards/{{dashboard_id}}