System tray menu items throw an exception

When using the menu items "New terminal" or "Show settings" in the system tray an unhandled exception occurs.
I have manually installed the app and did not test other ways to install it.

```
************** Exception Text **************
System.ComponentModel.Win32Exception (0x80004005): The system cannot find the file specified
at System.Diagnostics.Process.StartWithShellExecuteEx(ProcessStartInfo startInfo)
at System.Diagnostics.Process.Start(ProcessStartInfo startInfo)
at FluentTerminal.SystemTray.SystemTrayApplicationContext.NewWindow(Object sender, EventArgs e)
at System.Windows.Forms.MenuItem.OnClick(EventArgs e)
at System.Windows.Forms.MenuItem.MenuItemData.Execute()
at System.Windows.Forms.Command.Invoke()
at System.Windows.Forms.NotifyIcon.WndProc(Message& msg)
at System.Windows.Forms.NativeWindow.Callback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
```