Don't strip newline in esc_url() when protocol is mailto:

The mailto protocol is a bit different than the other protocols in that new lines are something you might realistically want to include. Includes tests to make sure that http protocol urls that contain mailto: aren't affected. Tests for stripping newlines in general already exist.

Fixes #31632
Props danielbachhuber


Built from https://develop.svn.wordpress.org/trunk@33064


git-svn-id: http://core.svn.wordpress.org/trunk@33035 1a063a9b-81f0-0310-95a4-ce76da25c4cd

wp-admin/about.php

@@ -41,7 +41,7 @@ include( ABSPATH . 'wp-admin/admin-header.php' );
 </h2>
 
 <div class="headline-feature feature-video">
-	<embed type="application/x-shockwave-flash" src="https://v0.wordpress.com/player.swf?v=1.04" width="1000" height="560" wmode="direct" seamlesstabbing="true" allowfullscreen="true" allowscriptaccess="always" overstretch="true" flashvars="guid=e9kH4FzP&amp;isDynamicSeeking=true"></embed>
+<iframe width="560" height="315" src="https://www.youtube.com/embed/LCZ-cxfxzvk" frameborder="0" allowfullscreen></iframe>
 </div>
 
 <hr />