Updates the icon and tip based on the validity of the array content.

def update_warning(self):
        """
        Updates the icon and tip based on the validity of the array content.
        """
        widget = self._button_warning
        if not self.is_valid():
            tip = _('Array dimensions not valid')
            widget.setIcon(ima.icon('MessageBoxWarning'))
            widget.setToolTip(tip)
            QToolTip.showText(self._widget.mapToGlobal(QPoint(0, 5)), tip)
        else:
            self._button_warning.setToolTip('')