(js) Fix display of auto-reply (vacation) message

Fixes #3940

NEWS

@@ -20,6 +20,7 @@ Bug fixes
  - [web] switch on "Remember username" when cookie username is set
  - [web] return login page for unknown users (#2135)
  - [web] fixed saving monthly recurrence rule with "by day" condition (#3948)
+ - [web] fixed display of message content when enabling auto-reply (#3940)
  - [eas] properly skip folders we don't want to synchronize (#3943)
  - [eas] fixed 30 mins freebusy offset with S Planner
 

UI/Templates/PreferencesUI/UIxPreferences.wox

@@ -826,7 +826,8 @@
                 <var:string label:value="Enable vacation auto reply"/>
               </md-checkbox>
 
-              <div class="md-inline-form" layout="column" flex-offset="5" ng-show="app.preferences.defaults.Vacation.enabled == 1">
+              <div class="md-inline-form" layout="column" flex-offset="5"
+                   ng-if="app.preferences.defaults.Vacation.enabled == 1">
 
                 <div layout="row">
                   <md-checkbox