Attempt to fix double goals

rust/src/goal.rs

@@ -38,7 +38,10 @@ impl IArea3D for Goal {
 
 impl Goal {
     fn on_enter(&self, node: Gd<Node3D>) {
-        if let Ok(_) = node.try_cast::<Ball>() {
+        if let Ok(mut ball) = node.try_cast::<Ball>()
+            && !ball.bind().entered_goal
+        {
+            ball.bind_mut().entered_goal = true;
             if let Some(mut game) = Game::singleton() {
                 let teams = game
                     .bind()

rust/src/player/ball.rs

@@ -12,6 +12,7 @@ use crate::{
 #[class(base=RigidBody3D, init)]
 pub struct Ball {
     pub dropper: Option<u16>,
+    pub entered_goal: bool,
 
     alive_for: f64,