refactor: simplify answer logic

src/routes/+page.svelte

@@ -1,8 +1,7 @@
 <script lang="ts">
   import { fade } from 'svelte/transition';
 
-  let hasImpact = false;
+  let hasImpact: boolean;
-  let hasAnswered = false;
 </script>
 
 <svelte:head>
@@ -18,23 +17,12 @@
 </header>
 
 <main>
-  {#if !hasAnswered}
+  {#if hasImpact === undefined}
     <form transition:fade={{ delay: 0, duration: 300 }}>
       <h1>Does this have impact?</h1>
 
-      <button
+      <button on:click={() => (hasImpact = true)}>Yes</button>
-        on:click={() => {
+      <button on:click={() => (hasImpact = false)}>No</button>
-          hasImpact = true;
-          hasAnswered = true;
-        }}>Yes</button
-      >
-
-      <button
-        on:click={() => {
-          hasImpact = false;
-          hasAnswered = true;
-        }}>No</button
-      >
     </form>
   {:else}
     <div transition:fade={{ delay: 300, duration: 500 }} id="answer">