curl: Use-after-free in `mev_forget_socket` when `curl_easy_pause()` is called from a `CURL_POLL_REMOVE` socket callback (incomplete fix of CVE-2026-9080)

Summary libcurl's event interface lets the application's socket callback CURLMOPTSOCKETFUNCTION call curleasypause. CVE-2026-9080 was issued for a use-after-free that this triggers, and the fix added a post-callback re-fetch of the socket-hash entry in the UPDATE leg mevshentryupdate,...