Fix wrong redirection when using custom pages + show flash messages

BT#17022

custompages/index-unlogged-dist.php

@@ -75,9 +75,12 @@ $rootWeb = api_get_path('WEB_PATH');
 		</div> <!-- #header -->
 		<div id="login-form-box" class="form-box">
             <div id="login-form-info" class="form-info">
-            <?php if (isset($content['info']) && !empty($content['info'])) {
+            <?php
-    echo $content['info'];
+                echo Display::getFlashToString();
-}
+                Display::cleanFlashMessages();
+                if (isset($content['info']) && !empty($content['info'])) {
+                    echo $content['info'];
+                }
             ?>
             </div>
             <?php if (isset($error_message)) {

main/auth/lostPassword.php

@@ -36,13 +36,13 @@ $tool_name = get_lang('LostPassword');
 if ($reset && $userId) {
     $messageText = Login::reset_password($reset, $userId, true);
 
-    if (CustomPages::enabled() && CustomPages::exists(CustomPages::INDEX_UNLOGGED)) {
+    /*if (CustomPages::enabled() && CustomPages::exists(CustomPages::INDEX_UNLOGGED)) {
         CustomPages::display(
             CustomPages::INDEX_UNLOGGED,
             ['info' => $messageText]
         );
         exit;
-    }
+    }*/
 
     Display::addFlash(
         Display::return_message($messageText, 'info', false)