XWIKI-17108: Emoji characters break PDF export

* Update the unit test

xwiki-platform-core/xwiki-platform-oldcore/src/test/resources/xhtml2fo.expected

 <?xml version="1.0" encoding="UTF-8"?>
-<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:html="http://www.w3.org/1999/xhtml" xmlns:svg="http://www.w3.org/2000/svg" writing-mode="lr-tb" hyphenate="false" text-align="start" font-family="FreeSans, AR PL UMing CN, sans-serif" role="html:html">
+<fo:root xmlns:fo="http://www.w3.org/1999/XSL/Format" xmlns:html="http://www.w3.org/1999/xhtml" xmlns:svg="http://www.w3.org/2000/svg" writing-mode="lr-tb" hyphenate="false" text-align="start" font-family="FreeSans, AR PL UMing CN, Noto Emoji, sans-serif" role="html:html">
 <fo:layout-master-set>
     <fo:simple-page-master page-width="auto" page-height="auto" master-name="first">
         <fo:region-body column-gap="12pt" column-count="1" margin-left="1in" margin-bottom="1in" margin-right="1in" margin-top="1in"/>