setting a block via `#enabled:` on a SpButtonPresenter raises `NonBooleanReceiver`.

[adri09070]

To reproduce:

• create a presenter composed of a list presenter and a button presenter.

• sets an enabled block that returns true if an item is selected in the list:

confirmButton := self newButton
		                 enabled: [
			                 chestsTable selectedItem notNil ];
		                 label: 'Confirm';
		                 yourself.

• open your presenter

• NonBooleanReceiver is raised

Expected behavior:

the documentation of SpAbstractWidgetPresenter>>#enabled: says I can give a block as an argument so I expect to be able to do it without preventing my presenter to open.