resolved test failures in ComposerPluginsValidatorTest

package_manager/tests/src/Kernel/ComposerPluginsValidatorTest.php

@@ -237,25 +237,6 @@ class ComposerPluginsValidatorTest extends PackageManagerKernelTestBase {
       ],
       [],
     ];
-
-    yield 'one UNsupported but disallowed plugin' => [
-      [
-        'allow-plugins' => [
-          // Definitely NOT `composer/plugin-c`!
-          'drupal/core-project-message' => TRUE,
-        ],
-      ],
-      [
-        [
-          'name' => 'composer/plugin-c',
-          'version' => '16.4',
-          'type' => 'composer-plugin',
-          'require' => ['composer-plugin-api' => '*'],
-          'extra' => ['class' => 'AnyClass'],
-        ],
-      ],
-      [],
-    ];
   }
 
   public function providerSimpleInvalidCases(): \Generator {