Ensure context is inherited in validation

actions-languageservice/src/utils/allowed-context.ts

@@ -1,11 +1,11 @@
 import {TemplateToken} from "@github/actions-workflow-parser/templates/tokens/template-token";
 
-export function getAllowedContext(token: TemplateToken, parent: TemplateToken): string[] {
+export function getAllowedContext(token: TemplateToken, parent: TemplateToken | null | undefined): string[] {
   // Workaround for https://github.com/github/c2c-actions-experience/issues/6876
   // Context is inherited from the parent
   const allowedContext = new Set<string>();
   for (const t of [token, parent]) {
-    if (t.definition?.readerContext) {
+    if (t?.definition?.readerContext) {
       for (const context of t.definition.readerContext) {
         allowedContext.add(context);
       }