Bug 420251

SUMMARY
Nothing happens when clicking "Connect" on a Wireguard connection under Sway WM in windowed mode.

STEPS TO REPRODUCE
1. Start a Sway WM session from SDDM
2. Open a terminal and execute `plasmawindowed org.kde.plasma.networkmanagement`
3. Wait (bug #420248)
4. Click on a connected wired network

OBSERVED RESULT

Visually nothing happens and on the terminal I see:
```
❯ plasmawindowed org.kde.plasma.networkmanagement
qt5ct: using qt5ct plugin
org.kde.plasmaquick: Applet preload policy set to 1
Couldn't start kglobalaccel from org.kde.kglobalaccel.service: QDBusError("org.freedesktop.DBus.Error.NoReply", "Did not receive a reply. Possible causes include: the remote application did not send a reply, the message bus security policy blocked the reply, the reply timeout expired, or the network connection was broken.")
org.kde.plasma: requesting config for "Networks" without a containment!
qml: 0
DBusMenu disabled for this application
QDBusObjectPath: invalid path ""
QDBusObjectPath: invalid path ""
QDBusObjectPath: invalid path ""
QDBusObjectPath: invalid path ""
```

EXPECTED RESULT
The Wireguard connection is established and Plasma Network Management displays this somehow.

SOFTWARE/OS VERSIONS
Operating System: Gentoo Linux 
KDE Plasma Version: 5.18.4
KDE Frameworks Version: 5.69.0
Qt Version: 5.14.2
Kernel Version: 5.6.4
OS Type: 64-bit
Processors: 8 × AMD Ryzen 5 2400G with Radeon Vega Graphics
Memory: 13.5 GiB of RAM
Sway WM: 1.4

ADDITIONAL INFORMATION
Plasma / Network Management Plasmoid has some trouble under Sway WM / Wayland:
* https://bugs.kde.org/show_bug.cgi?id=420248
* https://bugs.kde.org/show_bug.cgi?id=420243
* https://bugs.kde.org/show_bug.cgi?id=420249