Use file-chooser portal on Linux

[nojvspine]

Is your feature request related to a problem?

Some closed issues like #972 suggest that GTK or QT filechoosers are used depending on desktop environment. I use xdg-desktop-portal-termfilechooser and yazi as a file chooser and all other apps use it through file chooser portal. However Telegram still uses QT default file chooser.

Describe the solution you'd like

It would be nice if it used file chooser portal if present and defaulted to QT when necessary.

Describe alternatives you've considered

Testing shows that using QT_QPA_PLATFORMTHEME=xdgdesktopportal makes Telegram use proper filechooser, but this makes it impossible to use qt6ct as theme selector (I need it for matugen)

Additional context

No response

[ilya-fedin]

Sorry but Telegram is a Qt application and it has to use QFileDialog. If you don't like how Qt works, please discuss this with Qt developers.

[nojvspine]

I dug a bit into QFileDialog, I think I can just use QT_QPA_PLATFORMTHEME=xdgdesktopportal for Telegram since it doesn't have external theme management anyway

[ilya-fedin]

Doesn't qt6ct let you choose file dialog?

[nojvspine]

damn, literally didn't knew about this, now everything works, thanks!