Make sure to use gtk version 3 on Linux

https://www.electronjs.org/docs/latest/breaking-changes#changed-gtk-4-is-default-when-running-gnome

Signed-off-by: Jan Dubois <jan.dubois@suse.com>
(cherry picked from commit 9557453)

Author: jandubois

background.ts

@@ -56,6 +56,11 @@ import * as window from '@pkg/window';
 import { closeDashboard, openDashboard } from '@pkg/window/dashboard';
 import { openPreferences, preferencesSetDirtyFlag } from '@pkg/window/preferences';
 
+// https://www.electronjs.org/docs/latest/breaking-changes#changed-gtk-4-is-default-when-running-gnome
+if (process.platform === 'linux') {
+  Electron.app.commandLine.appendSwitch('gtk-version', '3');
+}
+
 Electron.app.setPath('userData', path.join(paths.appHome, 'electron'));
 Electron.app.setPath('cache', paths.cache);
 Electron.app.setAppLogsPath(paths.logs);