[CI Failure] GitHub artifact upload fails with 403 Forbidden from intermediary during FinalizeArtifact

## Build Information

Build: https://github.com/microsoft/aspire/actions/runs/31656131071
Build error leg: Tests / Templates-NewUpAndBuildStandaloneTemplateTests / Templates-NewUpAndBuildStandaloneTemplateTests (windows-latest)
Pull request: #19313

## Error Message

```
##[error]Failed to FinalizeArtifact: Received non-retryable error: Failed request: (403) Forbidden: Error from intermediary with HTTP status code 403 "Forbidden"
```

## Description

GitHub artifact upload fails with 403 Forbidden from intermediary during FinalizeArtifact

**Type**: infra-failure

## Occurrences

| Date | Build | Job | PR |
|------|-------|-----|----|
| 2026-08-13 | [31656131071](https://github.com/microsoft/aspire/actions/runs/31656131071) | Tests / Templates-NewUpAndBuildStandaloneTemplateTests / Templates-NewUpAndBuildStandaloneTemplateTests (windows-latest) | #19313 |
| 2026-09-08 | [34240101007](https://github.com/microsoft/aspire/actions/runs/34240101007) | Tests / No-package tests (regular, Aspire.Hosting.JavaScript.Tests, ...) / Hosting.JavaScript (windows-latest) | #19386 |
| 2026-09-08 | [34251319766](https://github.com/microsoft/aspire/actions/runs/34251319766) | Tests / No-package tests / Hosting-4 (windows-latest) | #19678 |

Start with the three linked GitHub Actions runs and their Windows job logs, comparing the artifact-upload failures around FinalizeArtifact. No repository file, test, or entry point is named; done would require identifying whether the 403 is actionable in this repository and recording or implementing a confirmed CI-level resolution.

Written by the indexing model from the issue text.