Use a custom widget with SegmentedButtonSlideEntry

[mateusfsilva]

Hi,

Thanks for the package.
In our project, we needed more complex text in the segmented button. To address this, I created a new property in the SegmentedButtonSlideEntry to receive a Widget and show it instead of the label and icon.

If you think this feature is helpful to other users, feel free to incorporate it into your package or change it to suit the package pattern better.

mateusfsilva@454138e