Fix the WordPress.org plugin preview

[dkotter]

Description of the Change

In #116 we added support for the WordPress.org plugin preview. As noted, testing that now results in an error.

Digging in I found two issues:

1. We use a importFile step but that has been removed in favor of importWxr
2. The landing page we send people to uses the post ID of 5 but seems that now gets imported with a post ID of 4

Both of these issues have been fixed in this PR.

How to test the Change

The WordPress Playground allows you to spin up a new environment directly through the URL, by going to https://playground.wordpress.net/# and pasting your JSON config after the #. In this case, the URL should be:

https://playground.wordpress.net/#{"$schema":"https://playground.wordpress.net/blueprint-schema.json","landingPage":"/wp-admin/post.php?post=4&action=edit","preferredVersions":{"php":"7.4","wp":"latest"},"phpExtensionBundles":["kitchen-sink"],"steps":[{"step":"login","username":"admin","password":"password"},{"step":"installPlugin","pluginZipFile":{"resource":"wordpress.org/plugins","slug":"retro-winamp-block"},"options":{"activate":true}},{"step":"importWxr","file":{"resource":"url","url":"https://raw.githubusercontent.com/10up/retro-winamp-block/d2ff63d1127713d9f2a11235a002f38f2927b0ca/.wordpress-org/blueprints/demo-data.xml"}}]}

Ensure that clicking that link loads a proper preview environment with the plugin installed and demo content loaded

Changelog Entry

Fixed - Ensure the WordPress.org plugin preview works as expected

Credits

Props @dkotter, @jeffpaul

Checklist:

• I agree to follow this project's Code of Conduct.
• I have updated the documentation accordingly.
• I have added tests to cover my change.
• All new and existing tests pass.

[jeffpaul]

@dkotter looks like some other plugins similarly use the older importFile notation... I assume its worth me pulling availability to help handle PRs on these others as well?

https://github.com/search?q=org%3A10up%20importFile&type=code

[dkotter]

looks like some other plugins similarly use the older importFile notation... I assume its worth me pulling availability to help handle PRs on these others as well?

Seems like importFile still works but recommended to replace with importWxr. The bigger issue here was the post ID changed from 5 to 4 (not sure why) so I'd say would be nice to get this updated anywhere we're using it but not critical