fix(core): swizzle --eject js should not copy theme .d.ts files

[slorber]

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.
• 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

Swizzle --eject of JS components (ie not using the --typescript option) should not emit any TS file (in particular the .d.ts files which are now published alongside the JS transpiled files)

Test Plan

Unit tests

Before:

yarn workspace website swizzle @docusaurus/theme-classic CodeBlock --eject
yarn workspace v1.22.17
yarn run v1.22.17
$ docusaurus swizzle @docusaurus/theme-classic CodeBlock --eject
[SUCCESS] 
Ejected CodeBlock from @docusaurus/theme-classic to 
- "/Users/sebastienlorber/Desktop/projects/docusaurus/website/src/theme/CodeBlock/index.d.ts"
- "/Users/sebastienlorber/Desktop/projects/docusaurus/website/src/theme/CodeBlock/index.js"

After:

yarn workspace website swizzle @docusaurus/theme-classic CodeBlock --eject
yarn workspace v1.22.17
yarn run v1.22.17
$ docusaurus swizzle @docusaurus/theme-classic CodeBlock --eject
[SUCCESS] 
Ejected CodeBlock from @docusaurus/theme-classic to 
- "/Users/sebastienlorber/Desktop/projects/docusaurus/website/src/theme/CodeBlock/index.js"

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[github-actions]

⚡️ Lighthouse report for the deploy preview of this PR

URL	Performance	Accessibility	Best Practices	SEO	PWA	Report
/	🟠 89	🟢 100	🟢 100	🟢 100	🟢 90	Report
/docs/installation	🟠 79	🟢 100	🟢 100	🟢 100	🟢 90	Report

[github-actions]

Size Change: 0 B

Total Size: 805 kB

ℹ️ View Unchanged

Filename	Size
website/.docusaurus/globalData.json	52.6 kB
website/build/assets/css/styles.********.css	106 kB
website/build/assets/js/main.********.js	607 kB
website/build/index.html	38.9 kB

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[slorber]

Not very satisfied with our swizzle tests atm

We'll likely want to create different fixtures for JS/TS as our current mixed JS/TS fixture does not really match the reality, ends up with ejecting only CSS files without components for example.

This will be good enough for now but we can do better