Update Skin & Name during play session

[yeslayla]

When a player updates their current skin or display name on the options screen while in a game (multiplayer or singleplayer), it should update as soon as the player exits the options screen.

[yeslayla]

#334 adds refresh_player_request(player_id) signal to network.gd and refresh_player(player_id) to game.gd which will reload the name and skin based on local player data.