UI: --install-firmware startup flag.

Has the normal UI flow, this is just for systems where the file picker doesn't show up.

src/Ryujinx.UI.Common/Helper/CommandLineState.cs

@@ -1,3 +1,4 @@
+using Gommon;
 using Ryujinx.Common.Logging;
 using System.Collections.Generic;
 using System.IO;
@@ -14,6 +15,7 @@ namespace Ryujinx.UI.Common.Helper
         public static string OverrideBackendThreading { get; private set; }
         public static string OverrideHideCursor { get; private set; }
         public static string BaseDirPathArg { get; private set; }
+        public static FilePath FirmwareToInstallPathArg { get; private set; }
         public static string Profile { get; private set; }
         public static string LaunchPathArg { get; private set; }
         public static string LaunchApplicationId { get; private set; }
@@ -43,6 +45,19 @@ namespace Ryujinx.UI.Common.Helper
 
                         BaseDirPathArg = args[++i];
 
+                        arguments.Add(arg);
+                        arguments.Add(args[i]);
+                        break;
+                    case "--install-firmware":
+                        if (i + 1 >= args.Length)
+                        {
+                            Logger.Error?.Print(LogClass.Application, $"Invalid option '{arg}'");
+
+                            continue;
+                        }
+
+                        FirmwareToInstallPathArg = new FilePath(args[++i]);
+
                         arguments.Add(arg);
                         arguments.Add(args[i]);
                         break;

src/Ryujinx/UI/ViewModels/MainWindowViewModel.cs

@@ -1229,7 +1229,7 @@ namespace Ryujinx.Ava.UI.ViewModels
             return false;
         }
 
-        private async Task HandleFirmwareInstallation(string filename)
+        public async Task HandleFirmwareInstallation(string filename)
         {
             try
             {