Disable connections not supported by proxies missing in 4.2

[gbdrbob]

Please provide the following information

qBittorrent version and Operating System

4.2.1 on Windows 10 x64 1903 (also confirmed on macOS)

If on linux, libtorrent-rasterbar and Qt version

N/A

What is the problem

Since qBitorrent 4.2.0 release the option to Disable connections not supported by proxies (documented here) is missing in the connection page of the options menu.

What is the expected behavior

Disable connections not supported by proxies should appear as an option.

Steps to reproduce

Install qBitorrent 4.2.1, open options menu, select connections page. Observe missing option in "Proxy server" section.

Extra info(if any)

Image of proxy options in 4.1.9.1:

Image of proxy options in 4.2.1:

[sledgehammer999]

When using libtorrent 1.2.x yhe option itself is removed, but the behavior is always enabled.
Link to libtorrent author's comment: arvidn/libtorrent#4172 (comment)
(the talk about force_proxy option)