fix: better handling of empty text node hydration

packages/svelte/tests/runtime-runes/samples/state-space/_config.js

@@ -1,12 +1,15 @@
 import { test } from '../../test';
 
 export default test({
-	html: `<button></button>`,
+	html: `<button type="button">Update Text</button><div></div>`,
 
 	async test({ assert, target }) {
 		const btn = target.querySelector('button');
 
 		await btn?.click();
-		assert.htmlEqual(target.innerHTML, `<button>foo</button>`);
+		assert.htmlEqual(
+			target.innerHTML,
+			`<button type="button">Update Text</button><div>updated</div>`
+		);
 	}
 });

packages/svelte/tests/runtime-runes/samples/state-space/main.svelte

@@ -1,5 +1,11 @@
 <script>
-    let foo = $state();
+	let text = $state('');
+
+	function update_text() {
+			text = 'updated';
+	}
 </script>
 
-<button on:click={() => foo = 'foo'}>{foo}</button>
+<button type="button" on:click={update_text}>Update Text</button>
+
+<div>{text}</div>

packages/svelte/tests/runtime-runes/samples/state-undefined/_config.js

@@ -1,15 +1,12 @@
 import { test } from '../../test';
 
 export default test({
-	html: `<button type="button">Update Text</button><div></div>`,
+	html: `<button></button>`,
 
 	async test({ assert, target }) {
 		const btn = target.querySelector('button');
 
 		await btn?.click();
-		assert.htmlEqual(
-			target.innerHTML,
-			`<button type="button">Update Text</button><div>updated</div>`
-		);
+		assert.htmlEqual(target.innerHTML, `<button>foo</button>`);
 	}
 });

packages/svelte/tests/runtime-runes/samples/state-undefined/main.svelte

@@ -1,11 +1,5 @@
 <script>
-	let text = $state('');
-
-	function update_text() {
-			text = 'updated';
-	}
+    let foo = $state();
 </script>
 
-<button type="button" on:click={update_text}>Update Text</button>
-
-<div>{text}</div>
+<button on:click={() => foo = 'foo'}>{foo}</button>