feat(theme-classic): allow className as option for type: "search"

[JPeer264]

Pre-flight checklist

• I have read the Contributing Guidelines on pull requests.
• If this is a code change: I have written unit tests and/or added dogfooding pages to fully verify the new behavior.
  • Could not find any tests for these changes. Please correct me if I am wrong.
• If this is a new API or substantial change: the PR has an accompanying issue (closes #0000) and the maintainers have approved on my working plan.

Motivation

Please refer to this issue comment
#7164 (comment)

Test Plan

I tried to use yarn lerna link and linked it in a new setup project but still got [ERROR] ValidationError: "navbar.items[0].className" is not allowed although it has been added to the Joi validation schema. I might need help on this part (cc: @slorber)

Test links

Deploy preview: https://deploy-preview-7357--docusaurus-2.netlify.app/
New changes: https://deploy-preview-7357--docusaurus-2.netlify.app/docs/api/themes/configuration#navbar-search

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[Josh-Cena]

Please add a test case for the validation schema, although it's kind of obvious that it will work. Unit tests are always more effective than yarn link 😉

[JPeer264]

@Josh-Cena I would be more than happy to add one, but could not find any tests there. Are there some existing which I overlooked? I am pretty sure I am not the first person adding tests for this

[Josh-Cena]

The tests are here: https://github.com/facebook/docusaurus/blob/main/packages/docusaurus-theme-classic/src/__tests__/validateThemeConfig.test.ts

[JPeer264]

Oh ya true. Just found them thanks, I will add them right away.

[JPeer264]

@Josh-Cena implementation wise (apart from the validation) there are no tests am I right?

[Josh-Cena]

No, we don't have theme tests yet😞 I think this is the best we can do. It doesn't look like it shouldn't work.

[JPeer264]

@Josh-Cena friendly ping :)

[Josh-Cena]

Yes, it's good from my side. However I'd also like to get @slorber's approval. He'd been unavailable for the past two weeks; I think he'll be back this week.

[slorber]

LGTM 👍

[Josh-Cena]

Thanks @JPeer264!