Get Dashboard Item Property

Returns the key and value of a dashboard item property.A dashboard item enables an app to add user-specific information to a user dashboard. Dashboard items are exposed to users as gadgets that users can add to their dashboards. For more information on how users do this, see [Adding and customizing gadgets](https://confluence.atlassian.com/x/7AeiLQ).When an app creates a dashboard item it registers a callback to receive the dashboard item ID. The callback fires whenever the it...