feat(toolbar): add onOutsideClick prop

[williamgrosset]

Overview

This PR adds an optional onOutsideClick callback prop to the Toolbar component.

From a UX perspective, "toolbars" should close by default on an outside click. Similar to how dropdowns are handled. Since the component itself does not handle visibility, we can add a prop for the consumer to make it easier to implement this behavior.

e.g

<Toolbar onOutsideClick={() => setOpen(false)}>
  ...
</Toolbar>

• Tested locally
• Added tests
• Backwards compatible (opt-in)

Thank you for the awesome library!