Fix App Check swallowing errors and returning cached token

Author: nermeen-mattar

.changeset/honest-days-lick.md

@@ -0,0 +1,5 @@
+---
+'@firebase/app-check': minor
+---
+
+Fix App Check swallowing errors and returning cached token

packages/app-check/src/api.ts

@@ -206,8 +206,8 @@ export async function getToken(
     appCheckInstance as AppCheckService,
     forceRefresh
   );
-  if (result.error) {
-    throw result.error;
+  if (result.internalError) {
+    throw result.internalError;
   }
   return { token: result.token };
 }