[CI Failure] dotnet tool restore fails with 'Connection reset by peer' during arcade tool restore

## 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

```
Unhandled exception: Unable to read data from the transport connection: Connection reset by peer. error MSB3073: The command ""...dotnet" tool restore --configfile "...NuGet.config"" exited with code 1. Build FAILED.
```

## Description

dotnet tool restore fails with 'Connection reset by peer' during arcade tool restore

**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 |

Start with GitHub Actions run 31269165475 and the Tests / Azure.Messaging.ServiceBus job, then inspect the reported dotnet tool restore command and its NuGet.config context. Done means the connection-reset cause is identified and the affected arcade tool restore path has a verified outcome.

Written by the indexing model from the issue text.