Radio_button default value

**Is your feature request related to a problem? Please describe.**

The radio buttons are generally used when only one item should be selected. However, in many cases I and maybe others have, when the user is presented with a new screen or something to select, there is nothing that should be selected until the user decides. However, using the radio buttons makes this confusing since a default item is required or is the first item.

**Describe the solution you'd like**

The solution would be allow the default value=None

**Describe alternatives you've considered**

Currently, I display checkboxes and when the user selects a checkbox, I switch over to radio buttons

**Additional context**
Add any other context or screenshots about the feature request here.

Thanks for your consideration