fix: various php notices (#3145)

* fix: notice

* fix: Trying to get property content of non-object at bridges/PcGamerBridge.php line 36

* fix: better exception message

* fix: strpos(): Non-string needles will be interpreted as strings in the future. Use an explicit chr() call to preserve the current behavior

bridges/ReutersBridge.php

@@ -420,7 +420,7 @@ class ReutersBridge extends BridgeAbstract
     {
         $description = '';
         foreach ($contents as $content) {
-            $data;
+            $data = '';
             if (isset($content['content'])) {
                 $data = $content['content'];
             }