Composer 1 provider files sometimes end up with 'error' as the sha256

Problem/Motivation

Using composer require/update when layout_builder_admin_theme is already in your codebase results in;

[Composer\Downloader\TransportException]                                                                                                 
  The "https://packages.drupal.org/8/drupal/layout_builder_admin_theme%24error.json" file could not be downloaded (HTTP/1.1 404 Not Found  
  )  

Steps to reproduce

composer require drupal/layout_builder_admin_theme

Or requiring another module when layout_builder_admin_theme is already present.

Proposed resolution

This looks like the same problem as #2855941: composer update/require fails for file_mdm 8.x-1.0 →