fix: detect payment form and wait or user input (#520)

Co-authored-by: Jens Bergmann <1742418+1cu@users.noreply.github.com>

src/kleinanzeigen_bot/extract.py

@@ -112,6 +112,7 @@ class AdExtractor(WebScrapingMixin):
         :param url: the URL to the ad page
         :return: the ad ID, a (ten-digit) integer number
         """
+
         num_part = url.rsplit("/", maxsplit = 1)[-1]  # suffix
         id_part = num_part.split("-", maxsplit = 1)[0]