disable the titlebar in qt apps

[Fuseteam]

this environment is used to enable hiding the titlebar in for example telegram telegramdesktop/tdesktop#26399

I have verified this variable works on my local setup

[Sunderland93]

Sway supports xdg-decoration-unstable-v1 protocol, which is used to determine what type of window decoration is wanted by the application: server-side (decoration provided by the window manager/compositor) or client-side (application draw the decoration on it's own). So there is no need to desable Qt's window decorations at all. The problem described in your link seems to be relevant only for the version of Telegram from the Ubuntu/Debian repositories. Are you using this version or installed from other sources (official website, Flatpak or Snap)?

[Fuseteam]

yet telegram's "use system decoration" doesn't work correctly, this fixes that
I'm using the official snap

btw the version from the ubuntu repositories is the snap version