[material-ui] Refine checkout template

[zanivan]

• I have followed (at least) the PR section of the contributing guide.

Part of #37555 / Closes #41098

This PR is for refining the checkout template to be aligned with the new landing page template.

Current	New

👉 https://deploy-preview-40967--material-ui.netlify.app/material-ui/getting-started/templates/checkout/

Note

The thumbnails and template's information will be updated last

[mui-bot]

Netlify deploy preview

https://deploy-preview-40967--material-ui.netlify.app/

Bundle size report

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Generated by 🚫 dangerJS against 257acbb

[danilo-leal]

We're getting there! Large review but mostly details. Also, heads-up to add theme customizations to the Alert component (that's too Material Design-y on the custom theme!)

[danilo-leal]

Looking great! Excited to have this one out, too — further improvements can come iteratively, in my perspective 🤙 And thanks for being so welcoming with the extensive feedback! 🙏

[zanivan]

@DiegoAndai I think this is ready for the engineering review 🙌 Would you mind giving me a hand with the failing tests?

[zanivan]

@DiegoAndai this file was created by docs:typescript:formatted, but I don't it's necessary. However, the tests fail when this file is not committed—what could be done then?

[DiegoAndai]

Weird 🤔 InfoMobile.tsx is the only file this is happening with? It looks like it's mistaking it for a docs demo. @mnajdova would you know anything about this?

[mnajdova]

We should only create preview files for the demos, not templates. I will look into updating the script. It was likely generated only for this file because there render is short (less than 15 lines of code I think was the minimum :))

[mnajdova]

Fixed in #41379. @zanivan you should remove the file after this PR is merged and it won't be generated anymore.

[DiegoAndai]

Looks good 🚀

Is the regression test failing consistently?

[DiegoAndai]

For the regression test failure, we need to exclude the getCheckoutTheme file as we did with the landing page: 11d46c7

We have to do this for all non-component files: #37557 (comment)