Sovereign Cloud - Update Azure Local registration region to Australia East

[Jan Egil Ring (janegilring)]

This pull request updates the lab’s default region for Azure Local registration and staging storage from West Europe to Australia East, clarifies the lab-only exception for this region, and improves error handling for Azure CLI failures. It also updates documentation, automation scripts, and test cases to reflect these changes and ensures that the new region is properly included in all policy allowlists and validation logic.

Region Default and Policy Updates:

• The default AzureLocalInstanceLocation is changed from 'westeurope' to 'australiaeast' in both automation (deploy-localbox.ps1, shared-deploy-lab.ps1) and manual setup scripts, as well as in test contracts and documentation. This makes Australia East the standard for lab deployments, independent of the Azure host region. [1] [2] [3] [4] [5] [6] [7] [8] [9] [10]
• All policy allowlists and related exercise instructions now explicitly include Australia East as a lab-only exception (not a European data-residency recommendation) alongside the four European regions. [1] [2] [3] [4]

Error Handling Improvements:

• The Invoke-AzJson helper is refactored to better capture and propagate Azure CLI errors, preserving native error details for regional fallback logic and avoiding leakage of sensitive command arguments or output. [1] [2]

Documentation and Guidance:

• All relevant documentation is updated to clarify the new default, the rationale for the Australia East exception, and the distinction between policy denials and regional ineligibility. Guidance is improved for organizers and participants regarding region selection, fallback, and error analysis. [1] [2] [3] [4] [5]

Testing Enhancements:

• Pester tests are updated to validate the new region default, ensure the policy allowlist includes all required regions, and verify that error handling and fallback logic behave as expected in various failure scenarios. [1] [2]

These changes ensure a consistent lab experience, clearer documentation, and more robust automation for region selection and error handling.