Fixes double escaping of messages

Passing null as the translation sanitization strategy disables it
which is safe in this case because the string is escaped when
rendered by angular.

#4618

static/js/services/format-data-record.js

@@ -244,7 +244,11 @@ angular.module('inboxServices').factory('FormatDataRecord',
         return getMessage(settings, key, locale) || key;
       }
       var interpolation = skipInterpolation ? 'no-interpolation' : null;
-      return $translate.instant(key, ctx, interpolation, locale);
+      // NB: The 5th parameter must be explicitely null to disable sanitization.
+      // The result will be sanitized by angular when it's rendered, so using
+      // the default sanitization would result in double encoding.
+      // Issue: medic/medic-webapp#4618
+      return $translate.instant(key, ctx, interpolation, locale, null);
     };
 
     /*