Expose an `Id` Bicep output reference for Azure Front Door

### Summary

The Aspire Azure Front Door resource should expose its resource ID as an `Id` Bicep output reference.

### Motivation

While adding Azure Front Door diagnostic settings in [dnceng/aspire-msft PR 64797](https://dev.azure.com/dnceng/aspire-msft/_git/aspire.dev/pullrequest/64797), the deployment needed the provisioned Front Door profile ID. Because the resource does not expose an `Id` output reference, the application had to add and consume a custom provisioning output.

An official output reference would let consumers pass the Front Door resource ID to diagnostic settings and other dependent infrastructure without duplicating provisioning logic.

### Proposed behavior

- Azure Front Door exposes an `Id` Bicep output reference for the provisioned profile resource ID.
- The output can be consumed by dependent resources through the standard Aspire resource-reference APIs.
- Provisioning tests verify the output name and generated Bicep value.

No file or test path is named in the issue. Start by locating the Azure Front Door resource provisioning entry point and existing provisioning tests for output references; verify that an Id output is emitted for the provisioned profile and can be consumed through standard resource-reference APIs.

Written by the indexing model from the issue text.