Updates an item in a collection.
This endpoint replaces the data item's existing data with the payload provided in dataItem.data in the request.
To update an item, you need to specify an item ID and a collection ID. If an item is found in the specified collection with the specified ID, that item is updated. If the collection doesn't contain an item with that ID, the request fails.
When an item is updated, its data._updatedDate field is changed to the current date and time.
Note:
After an item is updated, it only contains the fields included in the dataItem.data payload in Update Data Item request.
If the existing item has fields with values and those fields aren't included in the updated item, their values are lost.
You can only call this method when authenticated as a Wix app or Wix user identity.