Add support for sx prop with all mui-tiptap components for easier style overrides

[sjdemartini]

Is your feature request related to a problem? Please describe.

In order to more easily customize styles, each exported mui-tiptap component should ideally support sx for style customization, like all of MUI's components do, and not just allow for overrides via className.

Describe the solution you'd like

Perhaps we could just add wrappers that utilize styled https://mui.com/system/styled/ (in addition to or instead of some usage of tss-react), and/or would likely be beneficial to move to an approach like this https://mui.com/material-ui/customization/creating-themed-components/ instead of tss-react, to support styleOverrides as well (see #205).

Additional context

Would help with issues/questions like this #291 (comment).