Add AzureContainerRegistry network isolation policy to WebGPU/CUDA plugin EP package test pipelines (#31194)
### Description
<!-- Describe your changes. -->
Add AzureContainerRegistry network isolation policy to WebGPU/CUDA
plugin EP package test pipelines.
### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
Fix pipeline failures. The step to login to the container registry was
failing.