Configurable WSS streaming URL endpoint for Rekognition Face Liveness

### Before opening, please confirm:

- [x] I have [searched for duplicate or closed issues](https://github.com/aws-amplify/amplify-android/issues?q=is%3Aissue+) and [discussions](https://github.com/aws-amplify/amplify-android/discussions).

### Language and Async Model

Kotlin

### Amplify Categories

Predictions

### Describe the feature request

Make the "wss://streaming-rekognition.$region.$baseDomain:443" become configurable by user e.g. set the full URL or `$baseDomain` can be parameterized similar to `$region`.

This new feature will makes user able to create a custom WSS proxy to hide real AWS streaming URL.

Related codes:
[RunFaceLivenessSession.kt#L192](https://github.com/aws-amplify/amplify-android/blob/0b38b9138dcc80003cb3c2eeb5143d640021927c/aws-predictions/src/main/java/com/amplifyframework/predictions/aws/service/RunFaceLivenessSession.kt#L192)

[RunFaceLivenessSession.kt#L197](https://github.com/aws-amplify/amplify-android/blob/0b38b9138dcc80003cb3c2eeb5143d640021927c/aws-predictions/src/main/java/com/amplifyframework/predictions/aws/service/RunFaceLivenessSession.kt#L197)

Start with aws-predictions/src/main/java/com/amplifyframework/predictions/aws/service/RunFaceLivenessSession.kt at the linked lines where the streaming URL is constructed. Trace how the region and other session configuration reach that code, then determine where a full URL or configurable base domain should be supplied. Done means the Face Liveness streaming endpoint can be customized without changing the default behavior.

Written by the indexing model from the issue text.