Current Behavior 😯

When giving IconButton size properties medium and larger the size class is not set.

Expected Behavior 🤔

That MuiIconButton get MuiIconButton-sizeMedium and MuiIconButton-sizeLarge the same way as MuiIconButton-sizeSmall

Steps to Reproduce 🕹

<IconButton size="large">
  <FontAwesomeIcon icon={faPlay} />
  <FontAwesomeIcon icon={faChevronRight} />
</IconButton>

<IconButton size="medium">
  <FontAwesomeIcon icon={faPlay} />
  <FontAwesomeIcon icon={faChevronRight} />
</IconButton>

Your Environment 🌎