fix(v2): dynamic dark mode detection without toggle widget

[hmil]

Motivation

Dynamic automatic dark mode detection is disabled when the manual switch is hidden. But I want to enjoy the benefits of automatic dark-mode switching without showing the manual toggle.

See details in #3876

close #3876

Have you read the Contributing Guidelines on pull requests?

Yes

Test Plan

With the following config:

    colorMode: {
      defaultMode: 'light',
      disableSwitch: true, // Don't show manual switch
      respectPrefersColorScheme: true, // But respect user preference!
    },

🎥 before this fix
🎥 after this fix

Not shown in the screencasts: Currently, the correct color theme gets applied but only if you do a hard reload of the page. The difference that this fix makes is that you don't have to reload the page anymore.

Related PRs

none

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Hi @hmil!

Thank you for your pull request and welcome to our community. We require contributors to sign our Contributor License Agreement, and we don't seem to have you on file.

In order for us to review and merge your code, please sign at https://code.facebook.com/cla. If you are contributing on behalf of someone else (eg your employer), the individual CLA may not be sufficient and your employer may need to sign the corporate CLA.

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[hmil]

Please re-run the CLA check.

[github-actions]

Size Change: 0 B

Total Size: 157 kB

ℹ️ View Unchanged

Filename	Size	Change
website/build/blog/2017/12/14/introducing-docusaurus/index.html	20.7 kB	0 B
website/build/docs/introduction/index.html	180 B	0 B
website/build/index.html	5.84 kB	0 B
website/build/main.********.js	113 kB	0 B
website/build/styles.********.css	17.5 kB	0 B

_{compressed-size-action}

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[slorber]

thanks, that makes sense!

[github-actions]

⚡️ Lighthouse report for the changes in this PR:

Category	Score
🟢 Performance	91
🟢 Accessibility	99
🟢 Best practices	100
🟢 SEO	100
🟢 PWA	95

Lighthouse ran on https://deploy-preview-3877--docusaurus-2.netlify.app/classic/