Security: Send nocache headers for password protected posts to avoid reverse-proxy or CDNs caching

[devhaozi]

Trac ticket: https://core.trac.wordpress.org/ticket/61711

This PR add nocache headers for password protected posts to avoid reverse-proxy or CDNs caching.

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This Pull Request is for code review only. Please keep all other discussion in the Trac ticket. Do not merge this Pull Request. See GitHub Pull Requests for Code Review in the Core Handbook for more details.

[github-actions]

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Props haozi, brevilo.

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[github-actions]

Hi @devhaozi! 👋

Thank you for your contribution to WordPress! 💖

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[github-actions]

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[brevilo]

Just adding myself as the reporter of the proposed fix 😇 ...

[brevilo]

Linked accounts (sorry for the noise)...

[brevilo]

I reviewed and tested the patch against WP 6.7.1 and can confirm it to be working as expected.

Thanks 👍