Regression of `config` command arguments to string (should be array)

**Describe the bug**
PR #1504, which fixed variable interpolation in unquoted values (command and entrypoint), introduced a regression in how `podman-compose config `handles the type of `command` arguments.

**To Reproduce**
`docker-compose.yml`:
```
services:
test:
image: busybox
command: sleep infinity
```
Run command `podman-compose config`

**Expected behavior**
```
services:
test:
command:
- sleep
- infinity
image: busybox
```

**Actual behavior**
```
services:
test:
command: sleep infinity
image: busybox
```

**Environment:**
Debian GNU/Linux 13 (trixie)
Python 3.13.5
podman-compose version 1.6.0
podman version 5.4.2

**Additional context**
`podman-compose` should keep `command` arguments as an array and behave the same as `docker-compose` does:
```
$ docker-compose config
name: test-podman-compose
services:
test:
command:
- sleep
- infinity
image: busybox
networks:
default: null
networks:
default:
name: test-podman-compose_default
```

Start with the docker-compose.yml example and run `podman-compose config` to reproduce the scalar `command` output. Trace the config command's handling of unquoted command values, especially the regression introduced by PR #1504, and compare it with the expected output; done means `sleep infinity` is emitted as the array `sleep`, `infinity`.

Written by the indexing model from the issue text.