fix(sns-subscriptions): cannot add Lambda Subscription when using a Lambda Construct from a different Construct Library (#26206)

Fix the "is construct" check to ensure one can add a LambdaSubscription to an sns topic using the "addSubscription" method regardless of whether it came from a symlinked construct library or not.

Closes #24788.

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*By submitting this pull request, I confirm that my contribution is made under the terms of the Apache-2.0 license*

Author: mjeanroy

packages/aws-cdk-lib/aws-sns-subscriptions/lib/lambda.ts

@@ -24,7 +24,7 @@ export class LambdaSubscription implements sns.ITopicSubscription {
   public bind(topic: sns.ITopic): sns.TopicSubscriptionConfig {
     // Create subscription under *consuming* construct to make sure it ends up
     // in the correct stack in cases of cross-stack subscriptions.
-    if (!(this.fn instanceof Construct)) {
+    if (!Construct.isConstruct(this.fn)) {
       throw new Error('The supplied lambda Function object must be an instance of Construct');
     }