Allow the ability to disable data-theme and dir entirely

[paulpopus]

Would appreciate the ability to disable dir and data-theme entirely in the cases for when we have these provided from the top level in the html.

In our use case at Payload we have the toast container at the very top of our providers since everything else relies on toasts so we can't pass these values down like we would with any other component so ideally we can set these to undefined or false to completely omit the attributes.

[emilkowalski]

Renamed to data-sonner-theme in #560.