test(e2e): TypeCheck website/starter in min/max range of TS versions

[slorber]

Motivation

We have no tests covering that we keep supporting older versions of TypeScript.

As we upgrade TypeScript on our monorepo, it's easy to be misled and release some libs that are incompatible with former TS versions.

Now we ensure that our website + starter remains compatible with TS 5.1

Note, although v3.0 is supposed to support TS 5.0, I think it never actually worked in practice. I can't get it working and get errors such as:

I suspect this is a bug related to the newly released v5.0 moduleResolution "bundler", but can't be sure. Starting v5.1 it works fine.

Also I think it's not a bad idea to require TS 5.1 in Docusaurus v3, because it permits to use ReactNode instead of JSX.Element:
https://devblogs.microsoft.com/typescript/announcing-typescript-5-1/#decoupled-type-checking-between-jsx-elements-and-jsx-tag-types

Considering Docusaurus v3 was released after TS 5.1, I suspect it never worked under v5.0 and nobody noticed. So I'll bump the docs to mention v5.1 instead of v5.0 as the minimum version, and will not consider it as a breaking change.

Test Plan

CI

[netlify]

✅ [V2]

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 67	🟢 98	🟢 96	🟢 100	🟠 88	Report
/docs/installation	🟠 56	🟢 96	🟢 100	🟢 100	🟠 88	Report
/docs/category/getting-started	🟠 74	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog	🟠 68	🟢 100	🟢 100	🟢 90	🟠 88	Report
/blog/preparing-your-site-for-docusaurus-v3	🟠 63	🟢 96	🟢 100	🟢 100	🟠 88	Report
/blog/tags/release	🟠 69	🟢 100	🟢 100	🟠 80	🟠 88	Report
/blog/tags	🟠 76	🟢 100	🟢 100	🟢 90	🟠 88	Report

[github-actions]

Size Change: 0 B

Total Size: 1.59 MB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/codeTranslations.json	2 B
website/.docusaurus/docusaurus.config.mjs	26.7 kB
website/.docusaurus/globalData.json	91.2 kB
website/.docusaurus/i18n.json	930 B
website/.docusaurus/registry.js	247 kB
website/.docusaurus/routes.js	156 kB
website/.docusaurus/routesChunkNames.json	109 kB
website/.docusaurus/site-metadata.json	2.17 kB
website/build/assets/css/styles.********.css	113 kB
website/build/assets/js/main.********.js	810 kB
website/build/index.html	38 kB

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