fix(widgets): restore article table of contents behavior and styles

tests/widget-system/post-visual-contract.test.cjs

@@ -708,7 +708,7 @@ test('single articles enqueue only content and settings driven assets', () => {
   }
 
   assert.match(runtime, /wp:\(\?:code\|preformatted\|aksrt\\\/enlighter\)/);
-  assert.match(runtime, /preg_match_all\('\/<h\[1-4\]/);
+  assert.match(runtime, /\$requirements\['has_toc'\] = \$is_article && \$article_nav_enabled/);
   assert.match(runtime, /data-aksrt-video/);
   assert.match(runtime, /post_password_required\(\$post_id\)/);
   assert.match(runtime, /comment_settings\['close_comments'\]/);