Switched to Device code authentication

Worker.cs

@@ -5,6 +5,8 @@ namespace OneDriveBackupService;
 
 public class Worker(ILogger<Worker> logger, ConfigData config, OneDriveClient client) : BackgroundService {
     protected override async Task ExecuteAsync(CancellationToken stoppingToken) {
+        await client.EnsureAuthenticated(stoppingToken);
+        
         if (Environment.GetCommandLineArgs().Contains("--run-once")) {
             logger.LogInformation("Manual backup triggered");
             await RunBackup(DateTime.Now, stoppingToken);