Editor: add a classic block guide for users in deprecation group #4075986

Changes proposed in this Pull Request

• Add a custom editor guide for users in editor deprecation group to explain how to add a classic block

Testing instructions

• Set a user attribute for your user using wpsh on a sandbox $ update_user_attribute( USER_ID, ‘editor_deprecation_group’, true )
• Open the block editor a site and in Chrome dev tools select post-new.php as the javascript context and in console run wp.data.dispatch( 'core/edit-post' ).toggleFeature( 'welcomeGuide' ); – WPcom guide should load – don’t dismiss it
• Now check out this PR and build the wpcom block editor files with yarn build:prod in the apps/wpcom-block-editor/package.json folder.
• Sync the files created by the build in the ‘/dist’ folder with your sandbox widgets/wpcom-block-editor folder
• Also apply D45786-code to sandbox
• Make sure site used above is sandboxed Load editor editor again and make sure the Classic block guide loads instead of the standard WPcom guide
• Click the Get Started button to dismiss the dialog then reload page and make sure it does not display again (LocalStorage key for classic_block_guide_{siteID}_is_dismissed can be cleared to retest
• Also retest with a user that does not have ‘editor_deprecation_group’ and make sure the guide does not display

Screenshots

Fixes #43802