Fix quickbook. (#390)

Author: xiangkaiz

mcp_servers/quickbooks/session_manager.py

@@ -106,9 +106,6 @@ def extract_credentials_from_headers(self, request_or_scope) -> Tuple[str, str,
                 header_value = headers.get(b'x-auth-data')
                 if header_value:
                     auth_data = base64.b64decode(header_value).decode('utf-8')
-            
-            # Extract auth data from x-auth-data header
-            auth_data = base64.b64decode(headers.get(b'x-auth-data')).decode('utf-8')
 
         if not auth_data:
             return "", "", ""