Email: Mention free Proton account deletion

[dngray]

Changes proposed in this PR:

• Closes https://github.com/privacyguides/privacyguides.org/issues/2508

• [x] I have disclosed any relevant conflicts of interest in my post.
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[github-actions[bot]]

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[privacyguides-bot]

This pull request has been mentioned on Privacy Guides. There might be relevant details there:

https://discuss.privacyguides.net/t/2024-04-10/17801/1