Ensure that widget actions and filters get added for previewing snapshots for unauthenticated users

[westonruter]

The constructor for WP_Customize_Widgets has this bit of code before it does the add_action() and add_filter() calls:

// Skip useless hooks when the user can't manage widgets anyway.
if ( ! current_user_can( 'edit_theme_options' ) ) {
    return;
}

This will cause a problem for previewing widgets on the frontend for unauthenticated users because these filters/actions aren't getting added: https://github.com/xwp/wordpress-develop/blob/885d38edc8de04c3cf7baced5ef0effc8c5a6bd6/src/wp-includes/class-wp-customize-widgets.php#L101-L120

Snapshots should be adding these filters and actions (as required) if ! has_filter() or ! has_action().

[westonruter]

I haven't actually verified that this is actually an issue, but I can't see how it wouldn't be an issue 😄

[valendesigns]

@westonruter Well, it seems the issue is now much bigger than it was. I cannot see any new widgets in the Snapshot, regardless of if I'm authenticated or not. Even if I comment out that return.

[valendesigns]

@westonruter It appears to be an issue with the widget value not being set when saving the Snapshot for new widgets. I'm trying to hunt down the root issue, but if you have any suggestions that would be great. Perhaps there was a change in the widgets API that is causing this?