DO NOT MERGE Ensure BPD is available in execute()

Should not merge this because of https://github.com/nemiah/phpFinTS/blob/4bd1cecf823aaa506e216131146b2a6c7304be9e/lib/Fhp/FinTs.php#L631-L633 and because I'm not sure this will work dialog-wise.

lib/Fhp/FinTs.php

@@ -281,6 +281,9 @@ public function execute(BaseAction $action)
         if ($this->dialogId === null && !($action instanceof DialogInitialization)) {
             throw new \RuntimeException('Need to login (DialogInitialization) before executing other actions');
         }
+        if ($action instanceof PaginateableAction) {
+            $this->ensureBpdAvailable();
+        }
 
         $requestSegments = $action->getNextRequest($this->bpd, $this->upd);