Coding standards: Properly escape URLs returned by self_admin_url() calls.

Props krishaweb, audrasjb, SergeyBiryukov.
Fixes #56329.


git-svn-id: https://develop.svn.wordpress.org/trunk@53839 602fd350-edb4-49c9-b593-d223f7449a82

src/wp-admin/update-core.php

@@ -917,7 +917,7 @@ function do_core_upgrade( $reinstall = false ) {
 	?>
 	</div>
 	<script type="text/javascript">
-	window.location = '<?php echo self_admin_url( 'about.php?updated' ); ?>';
+	window.location = '<?php echo esc_url( self_admin_url( 'about.php?updated' ) ); ?>';
 	</script>
 	<?php
 }