fix: update VM size to Standard_D2s_v5 and update documentation for the same

[Harsh-Microsoft]

Purpose

This pull request updates the default jumpbox VM size to Standard_D2s_v5 across the deployment templates and documentation. It also improves troubleshooting guidance for VM SKU availability and ensures that the VM size can be customized via environment parameters. The most important changes are grouped below:

VM Size Default and Customization

• Changed the default jumpbox VM size from Standard_DS2_v2 to Standard_D2s_v5 in both infra/main.bicep and infra/main_custom.bicep, as well as in the ARM template output (infra/main.json). This provides a more current, cost-effective, and widely available VM option. [1] [2] [3]
• Added AZURE_ENV_VM_SIZE parameter to documentation and deployment templates, allowing users to override the default VM size for production deployments. [1] [2]

Documentation and Troubleshooting Improvements

• Enhanced troubleshooting documentation for the SkuNotAvailable error, including guidance on checking SKU availability, recommended alternatives, and explicit advice to avoid unsupported VM series.
• Updated VM size notes in infra/modules/virtualNetwork.bicep to reflect the new default and clarify recommended options.

Template and Dependency Updates

• Updated Bicep template generator version and template hashes in infra/main.json for consistency with the new deployment configuration. [1] [2] [3]
• Fixed resource dependency ordering in infra/main.json for private DNS zones, ensuring correct deployment sequencing. [1] [2]

Does this introduce a breaking change?

• Yes
• No

Golden Path Validation

• I have tested the primary workflows (the "golden path") to ensure they function correctly without errors.

Deployment Validation

• I have validated the deployment process successfully and all services are running as expected with this change.

What to Check

Verify that the following are valid

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Other Information