Convert some phutil_escape_html() to hsprintf()

Summary: Found by `sgrep_php -e '"...".phutil_escape_html(...)'`.

Test Plan:
/
/D1
/uiexample/
/countdown/1/
/herald/transcript/1/all/

Reviewers: epriestley

Reviewed By: epriestley

CC: aran, Korvin

Maniphest Tasks: T2432

Differential Revision: https://secure.phabricator.com/D4869

src/aphront/configuration/AphrontDefaultApplicationConfiguration.php

@@ -182,10 +182,9 @@ class AphrontDefaultApplicationConfiguration
         return $login_controller->processRequest();
       }
 
-      $content =
-        '<div class="aphront-policy-exception">'.
-          phutil_escape_html($ex->getMessage()).
-        '</div>';
+      $content = hsprintf(
+        '<div class="aphront-policy-exception">%s</div>',
+        $ex->getMessage());
 
       $dialog = new AphrontDialogView();
       $dialog