[IconButton] Fix border radius cutting of badges on IE11 (#12743)
[IconButton] Fix border radius cutting of badges on IE11 (#12743)

* [IconButton] Fix border radius cutting of badges on IE11

* Add a comment in case we forget why

mbrookes/material-ui,mbrookes/material-ui,kybarg/material-ui,callemall/material-ui,mui-org/material-ui,oliviertassinari/material-ui,Kagami/material-ui,mui-org/material-ui,kybarg/material-ui,mui-org/material-ui,lgollut/material-ui,kybarg/material-ui,oliviertassinari/material-ui,allanalexandre/material-ui,rscnt/material-ui,kybarg/material-ui,Kagami/material-ui,callemall/material-ui,callemall/material-ui,callemall/material-ui,mbrookes/material-ui,Kagami/material-ui,rscnt/material-ui,Kagami/material-ui,oliviertassinari/material-ui,rscnt/material-ui