[FEAT]: Support enterprise-level webhooks

### Describe the need

Pretty much what it says on the tin.

I'm using Terraform to create a webhook handler, from API Gateway to the handler Lambda, webhook secret, and everything.

The problem is this handler takes enterprise-level webhooks (for all orgs and repos therein). It looks like org-level and repo-level webhooks are supported, but not enterprise-level.

How hard would it be to implement this?

### SDK Version

_No response_

### API Version

_No response_

### Relevant log output

```shell

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### Code of Conduct

- [x] I agree to follow this project's Code of Conduct