Investigate setting Electron's proxy from user setting

<!-- ⚠️⚠️ Do Not Delete This! bug_report_template ⚠️⚠️ --> <!-- Please read our Rules of Conduct: https://opensource.microsoft.com/codeofconduct/ --> <!-- Please search existing issues to avoid creating duplicates. --> <!-- Also please test using the latest insiders build to make sure your issue has not already been fixed: https://code.visualstudio.com/insiders/ --> <!-- Use Help > Report Issue to prefill these. --> - VSCode Version: 1.43.2 - OS Version: Ubuntu 18.04 Steps to Reproduce: 1. Set proxy from OS, and in settings.json, but still can't browse or install extensions. Looking at log I get ERR_CONNECTION_TIMED_OUT