fix: acceptance of submission path

Author: Zicchio

pyeudiw/openid4vp/presentation_submission/__init__.py

@@ -109,6 +109,8 @@ def _extract_position(self, path: str) -> int:
         :return: Tuple of position and path.
         :rtype: tuple[str, str]
         """
+        if path == "$":
+            return 0
         pattern = r"\$[a-z_\-\.]*\[(\d+)\]"
         match = re.match(pattern, path, re.I)
         if match: