Dashicons: Update to the latest dashicons files.

props empireoflight, melchoyce.
see #26518 for trunk.
Built from https://develop.svn.wordpress.org/trunk@26925


git-svn-id: http://core.svn.wordpress.org/trunk@26806 1a063a9b-81f0-0310-95a4-ce76da25c4cd