docs(fab): Fixing documentation error for accessible mini FABs.
docs(fab): Fixing documentation error for accessible mini FABs.

HTML mistakenly included a `mdc-fab__label` element which would result in a misshapen FAB icon (as mini FABs don't support a label).

closes #6561

PiperOrigin-RevId: 339876886

material-components/material-components-web,material-components/material-components-web,material-components/material-components-web