[docs] Fix layout glitch when changing sort-by in showcases (#15255)
[docs] Fix layout glitch when changing sort-by in showcases (#15255)

Fixes https://github.com/mui-org/material-ui/issues/15244
mui-org/material-ui,kybarg/material-ui,rscnt/material-ui,kybarg/material-ui,kybarg/material-ui,mbrookes/material-ui,mui-org/material-ui,callemall/material-ui,mui-org/material-ui,callemall/material-ui,rscnt/material-ui,rscnt/material-ui,mbrookes/material-ui,lgollut/material-ui,kybarg/material-ui,callemall/material-ui,mbrookes/material-ui,allanalexandre/material-ui,callemall/material-ui,oliviertassinari/material-ui,oliviertassinari/material-ui,oliviertassinari/material-ui