Add test for role UI when using config translation

Problem/Motivation

The test was initially added to #2910353: Prevent saving config entities when configuration overrides are applied but we are trying to reduce the scope of this issue.
(It was historically about both detecting when configuration overrides are saved and fixing places where this happens.)
The test passes on main because the code that was incorrectly saving overrides has been fixed in another issue (probably #3497325: Config entity static cache is not cleared correctly when multiple language overrides are used) but the test still has value so we could commit it.

Steps to reproduce

The initial problem (now fixed) was that saving permissions could result in a translated role name being saved to the original untranslated config.
I don't have exact steps to reproduce because the bug has been fixed on main.

However it is possible to make the test fail with this change:

diff --git a/core/modules/user/user.module b/core/modules/user/user.module
index 53f0cdd5226..52b37c7265d 100644
--- a/core/modules/user/user.module
+++ b/core/modules/user/user.module
@@ -10,6 +10,7 @@
 use Drupal\Core\Session\AnonymousUserSession;
 use Drupal\Core\Site\Settings;
 use Drupal\Core\Url;
+use Drupal\user\Entity\Role;
 use Drupal\user\Entity\User;
 use Drupal\user\UserInterface;
 
@@ -465,8 +466,7 @@ function user_role_change_permissions($rid, array $permissions = []): void {
  */
 function user_role_grant_permissions($rid, array $permissions = []): void {
   // Grant new permissions for the role.
-  $role_storage = \Drupal::entityTypeManager()->getStorage('user_role');
-  if ($role = $role_storage->loadOverrideFree($rid)) {
+  if ($role = Role::load($rid)) {
     foreach ($permissions as $permission) {
       $role->grantPermission($permission);
     }
@@ -487,8 +487,7 @@ function user_role_grant_permissions($rid, array $permissions = []): void {
  */
 function user_role_revoke_permissions($rid, array $permissions = []): void {
   // Revoke permissions for the role.
-  $role_storage = \Drupal::entityTypeManager()->getStorage('user_role');
-  $role = $role_storage->loadOverrideFree($rid);
+  $role = Role::load($rid);
   foreach ($permissions as $permission) {
     $role->revokePermission($permission);
   }

(This is a revert from this commit: https://git.drupalcode.org/project/drupal/-/commit/30fb2bde8c479d9fd3be0...)

Proposed resolution

Add a functional test that checks if /admin/people/permissions works correctly with translated role labels.

Remaining tasks

User interface changes

Introduced terminology

API changes

Data model changes

Release notes snippet