Remove unused using directives and update nullability checks in various services

Author: xyzjesper

ByteMeBackup/Core/BackupTask.cs

@@ -1,5 +1,3 @@
-using System;
-using System.IO;
 using System.IO.Compression;
 using ByteMeBackup.Configuration;
 using ByteMeBackup.Services;
@@ -138,7 +136,7 @@ await LogAsync($"""
         }
     }
 
-    private async Task LogAsync(string message, string consoleMarkup = null)
+    private async Task LogAsync(string message, string consoleMarkup = null!)
     {
         if (!string.IsNullOrWhiteSpace(consoleMarkup))
             AnsiConsole.Markup(consoleMarkup + "\n");

ByteMeBackup/Services/ConfigService.cs

@@ -1,7 +1,4 @@
-using System;
-using System.IO;
 using System.Text.Json;
-using System.Threading.Tasks;
 using ByteMeBackup.Configuration;
 using Spectre.Console;
 

ByteMeBackup/Services/DiscordWebhookLogService.cs

@@ -18,7 +18,7 @@ public DiscordWebhookLogService(ConfigService configService)
     public async Task SendLogAsync(string message)
     {
         var config = ConfigService.Get();
-        if (string.IsNullOrEmpty(config.DiscordWebhookUrl))
+        if (string.IsNullOrEmpty(config!.DiscordWebhookUrl))
         {
             AnsiConsole.Markup("[red]Discord webhook URL is not configured![/]\n");
             return;

ByteMeBackup/Startup.cs

@@ -1,4 +1,3 @@
-using System.Threading.Tasks;
 using ByteMeBackup.Configuration;
 using ByteMeBackup.Services;
 using Spectre.Console;
@@ -7,7 +6,6 @@ namespace ByteMeBackup;
 
 public class Startup
 {
-    private static ConfigService ConfigService;
     private static AppConfig? Config;
 
     public static async Task Main()
@@ -18,7 +16,7 @@ public static async Task Main()
 
         AnsiConsole.Markup("[bold white]Starting ByteMeBackup...[/]\n");
 
-        if (Config.BackupConfigs.Length == 0)
+        if (Config!.BackupConfigs.Length == 0)
         {
             AnsiConsole.Markup("[red]No backup configurations found! Please check your config.json file.[/]\n");
             return;