Super Cache: add form to confirm deleting Boost advanced-cache.php

[donnchawp]

If the advanced-cache.php created by Jetpack Boost is found, the plugin displays a warning message saying that Boost must be deactivated before WP Super Cache can be used. This PR changes that message to a confirmation form that deletes the advanced-cache.php so that caching can be done by this plugin. Boost does not have to be deactivated.

ref: https://github.com/Automattic/jetpack/issues/37227

Proposed changes:

• add a new file inc/boost.php to hold Boost related functionality.
• The form, the code that handles submitting the form, and deleting the advanced-cache.php is in this file.
• Load that form from wp-cache.php
• Replace the original warning message with the form.

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

pc9hqz-2QH-p2

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

Testing instructions:

• Apply this PR using the beta plugin
• Activate Jetpack Boost and enable the Cache module.
• From the Plugins page, activate WP Super Cache.
• Go to the WP Super Cache settings page and note the new confirmation form that says Boost was found.
• Submit that form and the page will reload into the "Easy" settings page of the plugin.
• Visit the Boost settings page. The Cache module will be disabled but show a warning about the advanced-cache.php

Before:

After:

[github-actions[bot]]

Thank you for your PR!

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Super Cache plugin:

• Next scheduled release: June 4, 2024.
• Scheduled code freeze: May 27, 2024.

If you have any questions about the release process, please ask in the #jetpack-releases channel on Slack.

[haqadn]

p1716371347024369-slack-C016BBAFHHS