If a tool was not selected (i.e. user left the dropdown at "---------") when the user saves the tool, the server would result in an Internal Error.
This was due to the fact that we weren't handling the "empty" case when attempting to get the data from the widget.
Now we handle the empty case, which returns no data.

Create new configuration, or edit config:

   - No name + no tool -> both error

   - Name + no tool -> tool errors
Selecting a valid tool makes the error go away.
Error is "This field is required."