Added ui:enumDisabled to RadioWidget.js

[stamp]

Reasons for making this change

I noticed that ui:enumDisabled didn't work for the RadioWidget so I added it the same way it is implemented in the SelectWidget

Checklist

• I'm updating documentation
  • I've checked the rendering of the Markdown text I've added
  • If I'm adding a new section, I've updated the Table of Content
• I'm adding or updating code
  • I've added and/or updated tests
  • I've updated docs if needed
  • I've run npm run cs-format on my branch to conform my code to prettier coding style
• I'm adding a new feature
  • I've updated the playground with an example use of the feature

[glasserc]

Thanks!