Pass through input/hotkeys while Lua form is focused

to restore previous behaviour, call `forms.setproperty(form_handle,
"BlocksInputWhenFocused", true);`

src/BizHawk.Client.EmuHawk/MainForm.cs

@@ -519,6 +519,7 @@ namespace BizHawk.Client.EmuHawk
 					FormBase { BlocksInputWhenFocused: false } => AllowInput.All,
 					ControllerConfig => AllowInput.All,
 					HotkeyConfig => AllowInput.All,
+					LuaWinform { BlocksInputWhenFocused: false } => AllowInput.All,
 					_ => AllowInput.None
 				}
 			);

src/BizHawk.Client.EmuHawk/tools/Lua/LuaWinform.cs

@@ -13,6 +13,8 @@ namespace BizHawk.Client.EmuHawk
 		private readonly string _currentDirectory = Environment.CurrentDirectory;
 		private readonly LuaFile _ownerFile;
 
+		public bool BlocksInputWhenFocused { get; set; } = false;
+
 		public LuaWinform(LuaFile ownerFile, Action<IntPtr> formsWindowClosedCallback)
 		{
 			_ownerFile = ownerFile;