[CI Failure] Azure Functions Core Tools install fails with HTTP 404 from cdn.functions.azure.com

## Build Information

Build: https://github.com/microsoft/aspire/actions/runs/31269165475
Build error leg: Tests / Azure.Messaging.ServiceBus / Azure.Messaging.ServiceBus (ubuntu-latest)
Pull request: #19139

## Error Message

```
npm error attempting to GET "https://cdn.functions.azure.com/public/.../Azure.Functions.Cli.linux-x64....zip"
npm error Error downloading zip file from https://cdn.functions.azure.com/...
npm error Expected: 200, Actual: 404
```

## Description

Azure Functions Core Tools install fails with HTTP 404 from cdn.functions.azure.com

**Type**: infra-failure

## Occurrences

| Date | Build | Job | PR |
|------|-------|-----|----|
| 2026-08-08 | [31269165475](https://github.com/microsoft/aspire/actions/runs/31269165475) | Tests / Azure.Messaging.ServiceBus / Azure.Messaging.ServiceBus (ubuntu-latest) | #19139 |
| 2026-08-10 | [31362242749](https://github.com/microsoft/aspire/actions/runs/31362242749) | Tests / Playground / Playground (ubuntu-latest) | #19010 |
| 2026-09-14 | [34858055930](https://github.com/microsoft/aspire/actions/runs/34858055930) | Tests / No-package tests (regular, Aspire.Playground.Tests, Playground, Playground, tests/Aspire.Playgrou... / Playground (ubuntu-latest) | #19996 |

Start with build 31269165475 and the Tests / Azure.Messaging.ServiceBus / Azure.Messaging.ServiceBus job, then compare the other listed failing builds. Trace the Azure Functions Core Tools installation request to cdn.functions.azure.com and determine why the referenced zip returns 404; done means the affected Ubuntu jobs install the tool successfully.

Written by the indexing model from the issue text.