Support for VPC endpoint (multi-VPC private connectivity) for app runner applications

**Tell us about your request**
We would like to utilize VPC endpoints for the app runner application but this is not yet supported based on AWS documentation https://docs.aws.amazon.com/apprunner/latest/dg/security-vpce.html

**Additional context**
VPC endpoint support for app runner applications will allow clients to connect to the app runner application over PrivateLink while keeping all traffic within the AWS network. This would be a similar feature to the multi-vpc private connectivity currently available for the [Amazon MSK service](https://docs.aws.amazon.com/msk/latest/developerguide/aws-access-mult-vpc.html)

**Benefits of multi-VPC private connectivity**

Multi-VPC private connectivity has several advantages over other connectivity solutions:

- It automates operational management of the AWS PrivateLink connectivity solution.
- It allows overlapping IPs across connecting VPCs, eliminating the need to maintain non-overlapping IPs, complex peering, and routing tables associated with other VPC connectivity solutions.

**Attachments**

Start with the linked AWS App Runner VPC endpoint documentation and the Amazon MSK multi-VPC private connectivity documentation to understand the requested capability and constraints. Done means AWS App Runner supports connecting through VPC endpoints for multi-VPC private connectivity; this roadmap issue identifies no repository files or tests.

Written by the indexing model from the issue text.