Limit checkbox and radio interactive area to the control and label

[Spark450]

Summary

Update checkbox and radio button behaviour so the interactive area only includes the checkbox or radio element itself and its associated label text.

Acceptance criteria

• Checkbox interactive area is limited to the checkbox and its label
• Radio button interactive area is limited to the radio control and its label
• No extra clickable area exists beyond the end of the label
• Behaviour is consistent across supported implementations and states