PointerBox needs to support `sx` props

[dusave]

Describe the bug
PointerBox only allows use of bg, borderColor, etc. props to style it, but as advised, we are migrating to use sx instead. In this instance, it breaks the styling because sx props are not accounted for. Also, unless position: relative is supplied in the sx object, the Caret will render in the top left of the page as it blows away the local sx prop in the component, rather than doing a spread/object merge.

To Reproduce
Steps to reproduce the behavior:
Instantiate a PointerBox component using sx={{bg: '#ff0000'}} and notice that the background does not go red.

Expected behavior
It should either exclusively look for sx styling or use an either/or logic block to style the Caret

Screenshots

[rezrah]

@dusave - Just a heads up that this issue was resolved and is shipping in the next release.