[l10n] Stop re-exporting locales from package root

[LukasTy]

We currently re-export locales from in the root index file so that they are available from both import { frFR } from '@mui/x-data-grid' and import { frFR } from '@mui/x-data-grid/locales'.

mui-x/packages/grid/x-data-grid/src/index.ts

Line 13 in 947619d

export * from './locales';

We should avoid root-level exporting as it doesn't solve any particular problem besides making the package seem bulkier.

Related to mui/material-ui#39525

Search keywords:

[oliviertassinari]

making the package seem bulkier

Very much agree, it doesn't help market https://bundlephobia.com/package/@mui/x-data-grid@6.18.6

the reality is more:

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It also slows the load time when not using deep imports