[utils] Add typings for @mui-material/styles/cssUtils

[Semigradsky]

Fixed #29521

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[mui-pr-bot]

No bundle size changes

Generated by 🚫 dangerJS against 1fc88e3

[mnajdova]

This is not a public API, that's why we don't have types for them. I would even remove the unstable_* exports to be honest.

[Semigradsky]

Whats about usecase described in #29521? Maybe transformOrigin.horizontal/transformOrigin.vertical should accept string? In this case I will no need toUnitless.

[mnajdova]

Whats about usecase described in #29521? Maybe transformOrigin.horizontal/transformOrigin.vertical should accept string? In this case I will no need toUnitless.

Ok, I see your point. Let's add the types, but we also need to update the index.d.ts file to export these. Currently they are exported only from index.js. I would export again only the types for the utils that were available before:

export { getUnit as unstable_getUnit, toUnitless as unstable_toUnitless } from './cssUtils';

[hbjORbj]

LGTM. Thanks for your contribution!

[mnajdova]

Sorry for the delay. Looks good thanks. It's a great first pull request on MUI 👌