fix: bind:group incorrectly considers other groups for nested data

packages/svelte/tests/runtime-runes/samples/bind-group-nested-data/_config.js

@@ -0,0 +1,23 @@
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target, window, component }) {
+		const checkboxes = /** @type {NodeListOf<HTMLInputElement>} */ (
+			target.querySelectorAll('input[type="checkbox"]')
+		);
+
+		assert.isFalse(checkboxes[0].checked);
+		assert.isTrue(checkboxes[1].checked);
+		assert.isFalse(checkboxes[2].checked);
+
+		await checkboxes[1].click();
+
+		const noChecked = target.querySelector('#output')?.innerHTML;
+		assert.equal(noChecked, '');
+
+		await checkboxes[1].click();
+
+		const oneChecked = target.querySelector('#output')?.innerHTML;
+		assert.equal(oneChecked, 'Mint choc chip');
+	}
+});

packages/svelte/tests/runtime-runes/samples/bind-group-nested-data/main.svelte

@@ -0,0 +1,19 @@
+<script lang="ts">
+  import { writable } from 'svelte/store';
+
+  let menu = ['Cookies and cream', 'Mint choc chip', 'Raspberry ripple'];
+  let order = writable({ iceCream: [{flavours: ['Mint choc chip']}], scoops: 1 });
+  let index = 0
+</script>
+
+<form method="POST">
+  <input type="radio" bind:group={$order.scoops} name="scoops" value={1} /> One scoop
+  <input type="radio" bind:group={$order.scoops} name="scoops" value={2} /> Two scoops
+  <input type="radio" bind:group={$order.scoops} name="scoops" value={3} /> Three scoops
+
+  {#each menu as flavour}
+    <input type="checkbox" bind:group={$order.iceCream[index].flavours} name="flavours" value={flavour} /> {flavour}
+  {/each}
+</form>
+
+<div id="output">{$order.iceCream[index].flavours.join('+')}</div>