phosh: disable the qt gnome theming because qtdeclarative/qgnomeplatform does not cross compile

hosts/modules/gui/phosh.nix

@@ -49,6 +49,12 @@ in
     (mkIf cfg.enable {
       sane.programs.phoshApps.enableFor.user.colin = true;
 
+      # TODO(2023/02/28): remove this qt.style = "gtk2" override.
+      # gnome by default tells qt to stylize its apps similar to gnome.
+      # but the package needed for that doesn't cross-compile, hence i disable that here.
+      qt.platformTheme = "gtk2";
+      qt.style = "gtk2";
+
       # docs: https://github.com/NixOS/nixpkgs/blob/nixos-22.05/nixos/modules/services/x11/desktop-managers/phosh.nix
       services.xserver.desktopManager.phosh = {
         enable = true;