CheckboxControl: Add disabled state

[mirka]

What problem does this address?

#59364 surfaced a use case for a disabled state on CheckboxControl.

What is your proposed solution?

• Add appropriate styling (both for disabled and aria-disabled).
• Make sure the onChange is bypassed correctly in the aria-disabled case).
• As for the focus behavior when disabled, we may need an additional focusableWhenDisabled prop so consumers can choose (related: Make sure disabled buttons are always focusable by default #56547).