Service Attachment Type Missing From PolicyTargetReference Documentation

**Bug description**
The PolicyTargetReference [API docs](https://istio.io/latest/docs/reference/config/security/authorization-policy/) do not include a `Service` resource as a supported attachment type even though this type is reference in the [Ambient Getting Started](https://istio.io/latest/docs/ambient/getting-started/) guide.

**Affected product area (please put an X in all that apply)**

[ ] Configuration Infrastructure
[X] Docs
[ ] Installation
[ ] Networking
[ ] Performance and Scalability
[ ] Policies and Telemetry
[ ] Security
[ ] Test and Release
[ ] User Experience

**Expected behavior**
The ability to reference a Service in an auth policy but according to the API docs only a Gateway is supported.

**Steps to reproduce the bug**
Use the example provided in https://istio.io/latest/docs/reference/config/security/authorization-policy/

**Version (include the output of `istioctl version --remote` and `kubectl version`)**
1.22

**How was Istio installed?**
`istioctl install --set profile=ambient --skip-confirmation`

**Environment where bug was observed (cloud vendor, OS, etc)**
kind cluster

Additionally, please consider attaching a [cluster state archive](http://istio.io/help/bugs/#generating-a-cluster-state-archive) by attaching
the dump file to this issue.