fix(lambda-nodejs): cannot use .mts, .cts, and .cjs entry files (#25642)

This adds support for using TypeScript Module (`.mts`), TypeScript CommonJS (`.cts`) and JavaScript CommonJS (`.cjs`) entry files, as well as adding these to the default entry file search. 

This is a must for projects mixing ESM and CommonJS (quite common as not everything can/should be fully ESM yet) or where explicit file extension is desired.

I tried to follow the existing convention as best I could to keep it as simple as possible. I am not sure why the tests for the existing entry files are skipped as they seem to be working correctly, at least locally, so I enabled the new tests I added.

Closes #21635.

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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*

packages/@aws-cdk-testing/framework-integ/test/aws-lambda-nodejs/test/integ-handlers/cjs-handler.cjs

@@ -0,0 +1,7 @@
+/* eslint-disable no-console */
+const crypto = require('crypto');
+
+async function handler() {
+  console.log(crypto.createHash('sha512').update('cdk').digest('hex'));
+}
+module.exports = { handler }

packages/@aws-cdk-testing/framework-integ/test/aws-lambda-nodejs/test/integ-handlers/cts-handler.cts

@@ -0,0 +1,7 @@
+/* eslint-disable no-console */
+const crypto = require('crypto');
+
+async function handler(): Promise<void> {
+  console.log(crypto.createHash('sha512').update('cdk').digest('hex'));
+}
+module.exports = { handler }

packages/@aws-cdk-testing/framework-integ/test/aws-lambda-nodejs/test/integ-handlers/mts-handler.mts

@@ -0,0 +1,6 @@
+/* eslint-disable no-console */
+import * as crypto from 'crypto';
+
+export async function handler(): Promise<void> {
+  console.log(crypto.createHash('sha512').update('cdk').digest('hex'));
+}

packages/@aws-cdk-testing/framework-integ/test/aws-lambda-nodejs/test/integ.modules.js.snapshot/LambdaModulesDefaultTestDeployAssert7E536B97.assets.json

@@ -0,0 +1,32 @@
+{
+  "version": "31.0.0",
+  "files": {
+    "ae370e1010629b78f494346f49ceef3ab2875718f20e6c808114e6aa770c7bf3": {
+      "source": {
+        "path": "asset.ae370e1010629b78f494346f49ceef3ab2875718f20e6c808114e6aa770c7bf3.bundle",
+        "packaging": "zip"
+      },
+      "destinations": {
+        "current_account-current_region": {
+          "bucketName": "cdk-hnb659fds-assets-${AWS::AccountId}-${AWS::Region}",
+          "objectKey": "ae370e1010629b78f494346f49ceef3ab2875718f20e6c808114e6aa770c7bf3.zip",
+          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
+        }
+      }
+    },
+    "8a33a139431fff385be0d614ca0fa1d500235d787a28b7d7fc651257af8c722a": {
+      "source": {
+        "path": "LambdaModulesDefaultTestDeployAssert7E536B97.template.json",
+        "packaging": "file"
+      },
+      "destinations": {
+        "current_account-current_region": {
+          "bucketName": "cdk-hnb659fds-assets-${AWS::AccountId}-${AWS::Region}",
+          "objectKey": "8a33a139431fff385be0d614ca0fa1d500235d787a28b7d7fc651257af8c722a.json",
+          "assumeRoleArn": "arn:${AWS::Partition}:iam::${AWS::AccountId}:role/cdk-hnb659fds-file-publishing-role-${AWS::AccountId}-${AWS::Region}"
+        }
+      }
+    }
+  },
+  "dockerImages": {}
+}