Prevent TypeError when admin bar is manipulated.

Author: desrosj

src/wp-includes/admin-bar.php

@@ -971,8 +971,12 @@ function wp_admin_bar_command_palette_menu( WP_Admin_Bar $wp_admin_bar ): void {
 	 */
 	$function = <<<'JS'
 		( applePattern, appleOSLabel ) => {
-			if ( ( new RegExp( applePattern, 'i' ) ).test( navigator.userAgent ) ) {
-				document.querySelector( '#wp-admin-bar-command-palette .ab-label kbd' ).textContent = appleOSLabel;
+			if ( ! ( new RegExp( applePattern, 'i' ) ).test( navigator.userAgent ) ) {
+				return;
+			}
+			const kbd = document.querySelector( '#wp-admin-bar-command-palette .ab-label kbd' );
+			if ( kbd ) {
+				kbd.textContent = appleOSLabel;
 			}
 		}
 	JS;