fix modularizeImports with @mui/material (#51953)

Fixes #51872. We were exploring in
mui/material-ui#35457 the option to move the
`modularizeImports` config to our Next.js examples to fix
mui/material-ui#35450 however, we never got to
complete the work.

We are not yet in a position where we can apply modularizeImports to
`@mui/material`. We still have folders to create to make it work.

Maybe we should close mui/material-ui#35457?

Co-authored-by: JJ Kasper <jj@jjsweb.site>

packages/next/src/server/config.ts

@@ -693,9 +693,6 @@ function assignDefaults(
     '@mui/icons-material': {
       transform: '@mui/icons-material/{{member}}',
     },
-    '@mui/material': {
-      transform: '@mui/material/{{member}}',
-    },
     'date-fns': {
       transform: 'date-fns/{{member}}',
     },