added missing claszz

Author: StefanSpieker

core/src/main/resources/jenkins/model/GlobalQuietPeriodConfiguration/config.jelly

@@ -25,6 +25,6 @@ THE SOFTWARE.
 <?jelly escape-by-default='true'?>
 <j:jelly xmlns:j="jelly:core" xmlns:st="jelly:stapler" xmlns:d="jelly:define" xmlns:l="/lib/layout" xmlns:t="/lib/hudson" xmlns:f="/lib/form">
     <f:entry title="${%Quiet period}" field="quietPeriod">
-        <f:number min="0"/>
+        <f:number min="0" clazz="number"/>
     </f:entry>
 </j:jelly>