Draw the menu separator without Tailwind

The separator renders data-md-menu-separator and takes its 1px line,
8px block margin and 16px inset from menu-separator.css in
material.components (plan step 36, actions).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Qwx5USif3wFFmxtHg5U1g9

tests/Feature/Components/ActionStylesheetsTest.php

@@ -19,6 +19,7 @@ dataset('action components', [
     'button-group',
     'split-button',
     'fab',
+    'menu-separator',
 ]);
 
 it('draws the component from a stylesheet shaped like every package stylesheet', function (string $name) {