docker login is ignored on Docker Desktop with buildkit

Docker login is ignored in some cases when using `skaffold build`.

```sh
docker login -u="user" -p="secret" quay.io
docker build .
skaffold build
```

### Expected behavior

Both `docker build .` and `skaffold build` succeed.

### Actual behavior

`docker build .` succeeds while `skaffold build` fails.

### Information

- Skaffold version: v2.0.4
- Operating system: MacOS 13.1
- Installed via: homebrew
- Contents of skaffold.yaml:

```yaml
apiVersion: skaffold/v4beta1
kind: Config
metadata:
name: "service"
build:
artifacts:
- image: "service"
```

- Docker Desktop config on MacOS:

```
{
"builder": {
"gc": {
"defaultKeepStorage": "20GB",
"enabled": true
}
},
"experimental": false,
"features": {
"buildkit": true
}
}
```

- Dockerfile:

```
FROM quay.io/company/private-service
CMD ["echo", "success"]
```

### Steps to reproduce the behavior

1. create a private image on a registry
2. `docker login` to registry
3. use private image in Dockerfile
4. build with skaffold

### Workarounds

- disable buildkit in docker desktop or
- set `useBuildkit` in skaffold.yml