fix: avoid race condition when checking results

src/routes/game/+page.svelte

@@ -13,6 +13,7 @@
 
 	let mapPromise = $state(fetchMap());
 	let gamePromise = $state(fetchGame());
+	let isChecking = $state(false);
 	let results: CheckResponse | null = $state(null);
 
 	let currentIndex = $state(0);
@@ -63,7 +64,8 @@
 	}
 
 	async function checkLocation() {
-		if (!playerMarker || results) return;
+		if (!playerMarker || results || isChecking) return;
+		isChecking = true;
 
 		const gameData = await gamePromise;
 
@@ -96,6 +98,8 @@
 		} else {
 			alert("it seems than an error occurred");
 		}
+
+		isChecking = false;
 	}
 
 	async function restartGame() {
@@ -132,7 +136,7 @@
 
 		<div>
 			{#if results === null}
-				<button onclick={checkLocation} disabled={!playerMarker}>SUBMIT</button>
+				<button onclick={checkLocation} disabled={!playerMarker || isChecking}>SUBMIT</button>
 			{:else}
 				<button onclick={restartGame}>NEXT</button>
 			{/if}