Allow onValidateContact plugin to show error message (#37540)

Author: beefcakefu

components/com_contact/src/Controller/ContactController.php

@@ -171,12 +171,23 @@ public function submit()
         // Validation succeeded, continue with custom handlers
         $results = $this->app->triggerEvent('onValidateContact', [&$contact, &$data]);
 
+        $passValidation = true;
+
         foreach ($results as $result) {
             if ($result instanceof \Exception) {
-                return false;
+                $passValidation = false;
+                $app->enqueueMessage($result->getMessage(), 'error');
             }
         }
 
+        if (!$passValidation) {
+            $app->setUserState('com_contact.contact.data', $data);
+
+            $this->setRedirect(Route::_('index.php?option=com_contact&view=contact&id=' . $id . '&catid=' . $contact->catid, false));
+
+            return false;
+        }
+
         // Passed Validation: Process the contact plugins to integrate with other applications
         $this->app->triggerEvent('onSubmitContact', [&$contact, &$data]);