Polling is introduces spam in Tor logs. Also, Tor Browser 12.0 apparently has a bug where our polling renders the socks proxy unusuable after some time. see https://gitlab.torproject.org/tpo/applications/tor-browser/-/issues/41549 Instead of trying to detect a Tor socks proxy every 10 seconds, we now run detection when the Qt network dialog gets opened, and also when the user switches to the "Proxy" tab in the dialog. fixes https://github.com/spesmilo/electrum/issues/7317