Initial gold irrelevant

Hi GDQuest! Just wanting to quickly mention that, with this setup (and if I did not miss anything), we can buy any tower in the beginning of the game no matter how much gold we have. If I understood correctly, it is because Player is at the top of the scene tree, so when its gold setter function is called, the connection to the button's respective callback (where the button is disabled in case there's not enough gold to purchase the tower) is not made yet. Since I was not sure if it was a good idea to change the Player's place, i just added an extra call to _on_Player_gold_changed() at the end of set_player(), passing player.gold as an argument, and that seems to solve it. Not sure if that was the best fix, but my main point is to point it out in case this is remade for the Godot 4 courses (which I am very excited for, btw!!)