No "Use OpenSSH for Windows" checkbox on Windows

[ThinkChaos]

Expected Behavior

According to #1994, there should be a "Use OpenSSH for Windows instead of Pageant" checkbox in the SSH Agent settings.
I also check the develop branch and confirmed the checkbox still exists.

Current Behavior

The checkbox is not present.

Steps to Reproduce

1. Enable Windows 10's "OpenSSH Authentication Agent" (since 1803 "Spring Update")
2. Install the Windows build (tested w/ 2.3.4 and 2.4.0b2)
3. Enable SSH Agent in KeepassXC
4. Restart KeepassXC
5. Go back into the SSH Agent settings

Debug Info

KeePassXC - Version 2.3.4
Revision: 6fe821c

Libraries:

• Qt 5.11.1
• libgcrypt 1.8.3

Operating system: Windows 10 (10.0)
CPU architecture: x86_64
Kernel: winnt 10.0.17763

Enabled extensions:

• Auto-Type
• Browser Integration
• Legacy Browser Integration (KeePassHTTP)
• SSH Agent
• YubiKey

[droidmonkey]

This is available in 2.4.0, currently in beta2.