lint:container --resolve-env-vars fails on new project

### Symfony version(s) affected

7.2

### Description

Resolved value of "default:kernel.runtime_mode:" did not result in an array value.

![image](https://github.com/user-attachments/assets/1c4f9aed-cb42-4c00-8bdc-36eea7051bce)


### How to reproduce

```bash
symfony new --webapp env-var-demo
cd  env-var-demo
bin/console lint:container --resolve-env-vars
```

