Fix a deprecation warning that occurs when saving a wiki page 2, a=chris

diff --git a/src/controllers/components/SocialComponent.php b/src/controllers/components/SocialComponent.php
index 3c6fb9594..5b5e2facc 100644
--- a/src/controllers/components/SocialComponent.php
+++ b/src/controllers/components/SocialComponent.php
@@ -4164,7 +4164,7 @@ EOD;
                     $head_vars['page_type'] != 'standard')) {
                     $page = $head_string . "END_HEAD_VARS" . $page;
                 }
-                $page_info ??= [];
+                $page_info = (empty($page_info)) ? [] : $page_info;
                 $page_info['ID'] = $group_model->setPageName($user_id,
                     $group_id, $page_name, $page,
                     $data['CURRENT_LOCALE_TAG'], $edit_reason,