Remove 'secure' attribute from cookies in ProxyGenerator to ensure co…

[Luen]

Fix cookie transfer after CAPTCHA: strip secure before httpx Cookies.set()

When Google Scholar returns a CAPTCHA, the flow uses a browser to solve it, then copies cookies from the browser (Selenium) back into the httpx session so later requests use the same session. That copy step was raising:
TypeError: Cookies.set() got an unexpected keyword argument 'secure'
After that, the code retried with a new session, so the solved CAPTCHA session was effectively lost.

In _proxy_generator.py, _handle_captcha2() does:
Wait for the user to solve the CAPTCHA in the browser.
Call self._get_webdriver().get_cookies() (Selenium), which returns dicts that include browser-specific keys such as httpOnly, expiry, sameSite, and secure.
Strip only httpOnly, expiry, and sameSite, then call self._session.cookies.set(**cookie) (httpx).
httpx’s Cookies.set() does not accept a secure keyword. Passing the Selenium cookie dict as **cookie therefore included secure and triggered the TypeError.

Before calling self._session.cookies.set(**cookie), remove the secure key from each cookie dict, in the same way as the other non-httpx fields:
In _handle_captcha2(), add: cookie.pop("secure", None) after the existing pop calls for httpOnly, expiry, and sameSite.
With this, only supported arguments are passed to Cookies.set(), the cookie transfer completes, and the session continues to work after CAPTCHA solving without retrying due to this error.