add array check for $currentOpts

Co-authored-by: coderabbitai[bot] <136622811+coderabbitai[bot]@users.noreply.github.com>

Author: eug-L

prestashop8.x/controllers/admin/AdminTawktoController.php

@@ -243,7 +243,9 @@ public function ajaxProcessSetOptions()
         $currentOpts = Configuration::get($key);
         if (!empty($currentOpts)) {
             $currentOpts = json_decode($currentOpts, true);
-            $jsonOpts = array_merge($currentOpts, $jsonOpts);
+            if (is_array($currentOpts)) {
+                $jsonOpts = array_merge($currentOpts, $jsonOpts);
+            }
         }
 
         Configuration::updateValue($key, json_encode($jsonOpts));