Address PR comments

Author: hsubox76

packages/database/exp/register.ts

@@ -38,11 +38,7 @@ export function registerDatabase(variant?: string): void {
       (container, { instanceIdentifier: url }) => {
         const app = container.getProvider('app-exp').getImmediate()!;
         const authProvider = container.getProvider('auth-internal');
-        // App check is unsupported in Node.
-        const appCheckProvider =
-          variant === 'node'
-            ? undefined
-            : container.getProvider('app-check-internal');
+        const appCheckProvider = container.getProvider('app-check-internal');
         return repoManagerDatabaseFromApp(
           app,
           authProvider,

packages/storage/src/implementation/requests.ts

@@ -106,6 +106,8 @@ export function sharedErrorHandler(
     let newErr;
     if (xhr.getStatus() === 401) {
       if (
+        // This exact message string is the only consistent part of the
+        // server's error response that identifies it as an App Check error.
         xhr.getResponseText().includes('Firebase App Check token is invalid')
       ) {
         newErr = unauthorizedApp();