Widget param disableGrouping has wrong message when missing

[saumier]

The error message when the disableGrouping parameter is missing says disableGroups.

Expected behaviour: The name in the error message should be the same as the name of the parameter.

To do: The error message should be changed to disableGrouping. Otherwise, when manually configuring the widget it is not possible to know the name of the parameter to use from the error message.

The actual param needed by the widget is: disableGrouping

The error message for the widget says: disableGroups

[saumier]

@troughc This is a small fix that should be done quickly and before Verb starts using it because it will be visible to Verb. I took the initiative to set the priority to high.