feat(ec2): add APPCONFIG and APPCONFIGDATA to InterfaceVpcEndpointAwsService (#29408)

These are newly available as of [2023-12-11 (announcement)](https://aws.amazon.com/about-aws/whats-new/2023/12/aws-appconfig-supports-privatelink/) with endpoint names taken from the [AWS PrivateLink docs](https://docs.aws.amazon.com/vpc/latest/privatelink/aws-services-privatelink-support.html).

Testing: tried them in our environment. This PR is modeled after https://github.com/aws/aws-cdk/pull/21401/files, but the package.json code seems to be gone, and I didn't duplicate the verbose no-op tests that the string is the string.

### Reason for this change

New VPC Endpoints exist now.

### Description of changes

Add the missing constants.

### Description of how you validated changes

Tested `appconfigdata` in our account.

### Checklist
- [X/N/A] My code adheres to the [CONTRIBUTING GUIDE](https://github.com/aws/aws-cdk/blob/main/CONTRIBUTING.md) and [DESIGN GUIDELINES](https://github.com/aws/aws-cdk/blob/main/docs/DESIGN_GUIDELINES.md)

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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*

Yes, and I am an AWS employee.

Author: dhalperi

packages/aws-cdk-lib/aws-ec2/lib/vpc-endpoint.ts

@@ -268,6 +268,8 @@ export class InterfaceVpcEndpointAwsService implements IInterfaceVpcEndpointServ
   public static readonly APP_RUNNER = new InterfaceVpcEndpointAwsService('apprunner');
   public static readonly APP_RUNNER_REQUESTS = new InterfaceVpcEndpointAwsService('apprunner.requests');
   public static readonly APP_SYNC = new InterfaceVpcEndpointAwsService('appsync-api');
+  public static readonly APPCONFIG = new InterfaceVpcEndpointAwsService('appconfig');
+  public static readonly APPCONFIGDATA = new InterfaceVpcEndpointAwsService('appconfigdata');
   public static readonly APPLICATION_AUTOSCALING = new InterfaceVpcEndpointAwsService('application-autoscaling');
   public static readonly APPLICATION_MIGRATION_SERVICE = new InterfaceVpcEndpointAwsService('mgn');
   public static readonly APPSTREAM_API = new InterfaceVpcEndpointAwsService('appstream.api');