Simplifying context

Co-authored-by: Aaron Jorbin <aaronjorbin@users.noreply.github.com>

Author: t-hamano

src/wp-admin/theme-install.php

@@ -605,7 +605,7 @@
 			</div>
 		</div>
 		<div class="wp-full-overlay-main">
-		<iframe src="{{ data.preview_url }}" title="<?php echo esc_attr_x( 'Preview', 'noun, iframe title for the theme preview pane' ); ?>"></iframe>
+		<iframe src="{{ data.preview_url }}" title="<?php echo esc_attr_x( 'Preview', 'noun' ); ?>"></iframe>
 	</div>
 </script>