Added --backend-threading parameter for launching games via shortcut

src/Ryujinx/Program.cs

@@ -206,6 +206,16 @@ namespace Ryujinx.Ava
                     _ => ConfigurationState.Instance.Graphics.GraphicsBackend
                 };
 
+            // Check if backend threading was overridden
+            if (CommandLineState.OverrideBackendThreading is not null)
+                ConfigurationState.Instance.Graphics.BackendThreading.Value = CommandLineState.OverrideBackendThreading.ToLower() switch
+                {
+                    "auto" => BackendThreading.Auto,
+                    "off" => BackendThreading.Off,
+                    "on" => BackendThreading.On,
+                    _ => ConfigurationState.Instance.Graphics.BackendThreading
+                };
+
             // Check if docked mode was overriden.
             if (CommandLineState.OverrideDockedMode.HasValue)
                 ConfigurationState.Instance.System.EnableDockedMode.Value = CommandLineState.OverrideDockedMode.Value;