chore(route53): migrate existing record set handler (#28053)

This PR moves the delete existing record set handler from aws-cdk-lib to our new centralized location for custom resource handlers in the [@aws-cdk](https://github.com/aws-cdk) package.

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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: colifran

packages/@aws-cdk-testing/framework-integ/test/aws-route53/test/integ.delete-existing-record-set.js.snapshot/asset.482643dcf7106ecdc7f4ff9aefba13d1e5c7265377e6c6b9c77245f2bc55f6ef/index.js

@@ -151,7 +151,7 @@
      "S3Bucket": {
       "Fn::Sub": "cdk-hnb659fds-assets-${AWS::AccountId}-${AWS::Region}"
      },
-     "S3Key": "482643dcf7106ecdc7f4ff9aefba13d1e5c7265377e6c6b9c77245f2bc55f6ef.zip"
+     "S3Key": "a4d4a9308995dd99b8a8a3089e4f2087a577a6d3f8a3fc902354155a2b0b00c5.zip"
     },
     "Timeout": 900,
     "MemorySize": 128,

packages/@aws-cdk-testing/framework-integ/test/aws-route53/test/integ.delete-existing-record-set.js.snapshot/asset.482643dcf7106ecdc7f4ff9aefba13d1e5c7265377e6c6b9c77245f2bc55f6ef/__entrypoint__.js renamed to packages/@aws-cdk-testing/framework-integ/test/aws-route53/test/integ.delete-existing-record-set.js.snapshot/asset.a4d4a9308995dd99b8a8a3089e4f2087a577a6d3f8a3fc902354155a2b0b00c5/__entrypoint__.js

@@ -1,4 +1,4 @@
-import { handler } from '../lib/delete-existing-record-set-handler';
+import { handler } from '../../lib/aws-route53/delete-existing-record-set-handler';
 
 const mockListResourceRecordSetsResponse = jest.fn();
 const mockChangeResourceRecordSetsResponse = jest.fn();

packages/@aws-cdk-testing/framework-integ/test/aws-route53/test/integ.delete-existing-record-set.js.snapshot/asset.a4d4a9308995dd99b8a8a3089e4f2087a577a6d3f8a3fc902354155a2b0b00c5/index.js

@@ -269,7 +269,7 @@ export class RecordSet extends Resource implements IRecordSet {
     if (props.deleteExisting) {
       // Delete existing record before creating the new one
       const provider = CustomResourceProvider.getOrCreateProvider(this, DELETE_EXISTING_RECORD_SET_RESOURCE_TYPE, {
-        codeDirectory: path.join(__dirname, 'delete-existing-record-set-handler'),
+        codeDirectory: path.join(__dirname, '..', '..', 'custom-resource-handlers', 'dist', 'aws-route53', 'delete-existing-record-set-handler'),
         runtime: CustomResourceProviderRuntime.NODEJS_18_X,
         policyStatements: [{ // IAM permissions for all providers
           Effect: 'Allow',