Update PHP version in blueprint.json to 8.3 and removing deprecated step

[fellyph]

The blueprint was crashing on the live preview. I have updated the step that was causing the issue, this is the test of the changes:

https://playground.wordpress.net/builder/builder.html#{%22$schema%22:%22https://playground.wordpress.net/blueprint-schema.json%22,%22landingPage%22:%22/wp-admin/post.php?post=6&action=edit%22,%22preferredVersions%22:{%22php%22:%228.3%22,%22wp%22:%22latest%22},%22phpExtensionBundles%22:[%22kitchen-sink%22],%22steps%22:[{%22step%22:%22login%22,%22username%22:%22admin%22,%22password%22:%22password%22},{%22step%22:%22installPlugin%22,%22pluginData%22:{%22resource%22:%22wordpress.org/plugins%22,%22slug%22:%22safe-svg%22},%22options%22:{%22activate%22:true}},{%22step%22:%22importFile%22,%22file%22:{%22resource%22:%22url%22,%22url%22:%22https://raw.githubusercontent.com/10up/safe-svg/ec6071406de403e9c9f4b5833abf4e438816df05/.wordpress-org/blueprints/demo-data.xml%22}}],%22features%22:{},%22login%22:true}

Description of the Change

The live preview button wasn't working at the plugins repository:

This change removes the outdated step and updates the PHP version to 8.3

Closes #

How to test the Change

check the preview of the new blueprint

Changelog Entry

Added - New feature Changed - Existing functionality Deprecated - Soon-to-be removed feature Removed - Feature Fixed - Bug fix Security - Vulnerability Developer - Non-functional update

Credits

Props @username, @username2, ...

Checklist:

• [ ] I agree to follow this project's Code of Conduct.
• [ ] I have updated the documentation accordingly.
• [ ] I have added Critical Flows, Test Cases, and/or End-to-End Tests to cover my change.
• [ ] All new and existing tests pass.