fix(har timing): record connect timing for proxied connections (#32855

)

Fixes a bug discovered in
#32647. When using http
proxy, the `connect` event isn't emitted so we don't populate
`tcpConnectionAt`. The updated version of `https-proxy-agent` emits a
`proxyConnect` as a replacement, so this PR updates and listens to that
event.
For socks proxies, the `on("socket")` event is emitted once the SOCKS
connection is established, which is the equivalent of having a TCP
connection available.

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Signed-off-by: Simon Knott <info@simonknott.de>
Co-authored-by: Max Schmitt <max@schmitt.mx>