Customizer: Fix form tag replacement in WP_Customize_Widgets::get_widget_control() after [31200].

see #30126.

git-svn-id: https://develop.svn.wordpress.org/trunk@31226 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-includes/class-wp-customize-widgets.php

@@ -956,7 +956,7 @@ final class WP_Customize_Widgets {
 
 		call_user_func_array( 'wp_widget_control', $args );
 		$replacements = array(
-			'<form action="" method="post">' => '<div class="form">',
+			'<form method="post">' => '<div class="form">',
 			'</form>' => '</div><!-- .form -->',
 		);