[Document] Upload not work, docs/blob/develop2/ci_tutorial/packages_pipeline/multi_configuration.rst

https://github.com/conan-io/docs/blob/develop2/ci_tutorial/packages_pipeline/multi_configuration.rst

```
$ cd ai # If you were not inside "ai" folder already
$ conan create . --build="missing:ai/*" -s build_type=Release --format=json > graph.json
$ conan list --graph=graph.json --graph-binaries=build --format=json > built.json

$ conan remote enable packages
$ conan upload -l=built.json -r=packages -c --format=json > uploaded_release.json
$ conan remote disable packages
```

Upload not work, Prompt: WARN: No packages were uploaded because the package list is empty.

It's OK if change `conan list --graph=graph.json --graph-binaries=build --format=json > built.json` to `conan list --graph=graph.json --format=json > built.json`