context.cookies() with no argument returns every cookie in the browser
context, so a page that loads adverts hands the client cookies for dozens
of unrelated domains. One malformed third-party value is enough to make a
client discard the whole jar, cf_clearance with it, and the solve looks
like it failed.
Scope the call to the requested URL, plus the final page URL when a
redirect moved it. That matches what Selenium gave FlareSolverr, which is
the shape its clients are written against.
