chore: add test to show usage of context in component template (#11061)

* chore: prevent usage of getContext during component template

* repurpose test to be just a test to capture context in template

packages/svelte/tests/runtime-legacy/samples/context-in-template/_config.js

@@ -0,0 +1,7 @@
+import { test } from '../../test';
+
+export default test({
+	async test({ assert, target }) {
+		assert.htmlEqual(target.innerHTML, `hello world`);
+	}
+});

packages/svelte/tests/runtime-legacy/samples/context-in-template/main.svelte

@@ -0,0 +1,11 @@
+<script>
+	import { getContext, setContext } from 'svelte';
+
+	setContext('val', 'hello world')
+
+	const get_val = () => {
+		return getContext('val');
+	}
+</script>
+
+{get_val()}