Fix activating browser windows on Wayland

QDesktopServices::openUrl does not have XDG activation support yet so it can't raise an existing browser window when opening URLs

Instead use KIO::OpenUrlJob, which does support that

src/CMakeLists.txt

@@ -36,6 +36,7 @@ add_executable(neochat
     blurhashimageprovider.cpp
     joinrulesevent.cpp
     collapsestateproxymodel.cpp
+    urlhelper.cpp
     ../res.qrc
 )