Add autocomplete=email to Subscriptions form email input field

[westonruter]

Proposed changes:

• Add autocomplate="email" to the Subscriptions form email input field(s).

I noticed in Chrome DevTools that it identifies the lack of autocomplete as an issue:

Clearly Chrome is still able to autocomplete this field just fine, but it supplying the autocomplete attribute makes this issue go away and it makes the field even more explicit an email.

Other information:

• Have you written new tests for your changes, if applicable?
• Have you checked the E2E test CI results, and verified that your changes do not break them?
• Have you tested your changes on WordPress.com, if applicable (if so, you'll see a generated comment below with a script to run)?

Jetpack product discussion

Does this pull request change what data or activity we track or use?

Testing instructions:

• View a Subscriptions form on the frontend.
• Look at the email input field to see if it has autocomplete=email.
• Verify that your email can be autofilled.

[github-actions]

Thank you for your PR!

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🔴 Action required: Please add missing changelog entries for the following projects: projects/plugins/jetpack

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Jetpack plugin:

The Jetpack plugin has different release cadences depending on the platform:

• WordPress.com Simple releases happen as soon as you deploy your changes after merging this PR (PCYsg-Jjm-p2).
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  • Scheduled release: September 2, 2025
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[simison]

type="email"tends to in practise cover this, but good find! Asked Loop team for review & handle merging.