fix: Example Body Content Overflow with support for keyboard scroll (#…

…2225)

Fixes: #2222  

Keyboard accessibility: the scrollable area in the Body Content Overflow example of a modal could not be scrolled up/down using the keyboard only.

[category:Component Examples]

Release Note:
Adding tabIndex 0 to Modal.Body will allow for content to be accessible and scrollable if the content overflows

Co-authored-by: @mannycarrera4 <mannycarrera4@users.noreply.github.com>

modules/react/modal/stories/examples/BodyOverflow.tsx

@@ -20,7 +20,7 @@ export const BodyOverflow = () => {
         <Modal.Card>
           <Modal.CloseIcon aria-label="Close" />
           <Modal.Heading>MIT License</Modal.Heading>
-          <Modal.Body>
+          <Modal.Body tabIndex={0}>
             <p style={{marginTop: 0}}>
               Permission is hereby granted, free of charge, to any person obtaining a copy of this
               software and associated documentation files (the "Software"), to deal in the Software