Fix #94888, preferences sync gets reenabled on reload

src/vs/platform/environment/common/environment.ts

@@ -39,7 +39,7 @@ export interface IEnvironmentService {
 	// --- settings sync
 	userDataSyncLogResource: URI;
 	userDataSyncHome: URI;
-	sync: 'on' | 'off';
+	sync: 'on' | 'off' | undefined;
 
 	// --- extension development
 	debugExtensionHost: IExtensionHostDebugParams;

src/vs/platform/environment/node/environmentService.ts

@@ -92,7 +92,7 @@ export class EnvironmentService implements INativeEnvironmentService {
 	get userDataSyncLogResource(): URI { return URI.file(path.join(this.logsPath, 'userDataSync.log')); }
 
 	@memoize
-	get sync(): 'on' | 'off' { return this.args.sync === 'off' ? 'off' : 'on'; }
+	get sync(): 'on' | 'off' | undefined { return this.args.sync; }
 
 	@memoize
 	get machineSettingsResource(): URI { return resources.joinPath(URI.file(path.join(this.userDataPath, 'Machine')), 'settings.json'); }