Invalid display 'system'; display plugin not loaded unless admin_views module installed

Problem/Motivation

README states

"Included in this package is the Admin Views System Display module, which will be
automatically installed when Administration Views module itself is installed. It
may also be used on its own, should a site want to override system pages without
needing to use the included default displays."

However, if admin_views is uninstalled the "system" display plugin is no longer loaded.

In commit https://git.drupalcode.org/project/admin_views/-/commit/797c11529d88ab83... for issue #2411193: Move 'system' display plugin to a submodule → the function admin_views_views_plugins() was renamed to admin_views_system_display_views_plugins(), however the file name was not changed from admin_views.views.inc to admin_views_system_display.views.inc.

Steps to reproduce

Via UI:

Clone a default admin_views views e.g. Administration: Nodes.
Uninstall admin_views module.
Attempt to edit cloned view via UI, views ui will be blank.
List views plugins via CLI e.g. drush php:

$plugins = views_plugin_list();
$plugins['display:system']; // "module" property will be empty, expect "module" => "views"

Proposed resolution

Rename file admin_views.views.inc to admin_views_system_display.views.inc.

Remaining tasks

User interface changes

API changes

Data model changes