Don't send the welcome message when loading

Don't re-send the welcome message when loading the game if it's already
been sent. This is done by just tracking whether or not we've sent it as
a boolean in the game state, which may be a bit of a hack but should be fine

src/Xanthous/Game/Lenses.hs

@@ -50,6 +50,7 @@ initialStateFromSeed seed =
       _debugState = DebugState
         { _allRevealed = False
         }
+      _sentWelcome = False
   in GameState {..}