chore: prevent usage of getContext during component template

Author: trueadm

.changeset/young-pillows-join.md

@@ -0,0 +1,5 @@
+---
+"svelte": patch
+---
+
+chore: prevent usage of getContext during component template

packages/svelte/src/internal/client/runtime.js

@@ -949,7 +949,11 @@ export function getAllContexts() {
 /** @returns {Map<unknown, unknown>} */
 function get_or_init_context_map() {
 	const component_context = current_component_context;
-	if (component_context === null) {
+	if (
+		component_context === null ||
+		current_effect === null ||
+		(current_effect.f & BRANCH_EFFECT) === 0
+	) {
 		throw new Error(
 			'ERR_SVELTE_ORPHAN_CONTEXT' +
 				(DEV ? 'Context can only be used during component initialisation.' : '')