Customize: Ensure that "Change" button appears when there are only 2 themes.

Fixes defect introduced in [35535].

Props igmoweb.
See #34549.
Fixes #35081.

Built from https://develop.svn.wordpress.org/trunk@35943


git-svn-id: http://core.svn.wordpress.org/trunk@35907 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-includes/customize/class-wp-customize-themes-section.php

@@ -46,7 +46,7 @@ class WP_Customize_Themes_Section extends WP_Customize_Section {
 				}
 				?>
 
-				<?php if ( count( $this->controls ) > 1 ) : ?>
+				<?php if ( count( $this->controls ) > 0 ) : ?>
 					<button type="button" class="button change-theme" tabindex="0"><?php _ex( 'Change', 'theme' ); ?></button>
 				<?php endif; ?>
 			</h3>