Runtime incus is not respected in template

### Description

It seems to be a bug in v0.7.0 that you have to explicitly pass `--runtime incus` to `colima start` in the command line to make `colima` start with that runtime. Otherwise, listing it in the template yaml has no effect and `colima` starts with `docker` runtime.

### Version

0.7.0

### Operating System

- [ ] macOS Intel <= 13 (Ventura)
- [ ] macOS Intel >= 14 (Sonoma)
- [ ] Apple Silicon <= 13 (Ventura)
- [X] Apple Silicon >= 14 (Sonoma)
- [ ] Linux

### Output of `colima status`

```bash
$ colima status
INFO[0015] colima is running using macOS Virtualization.Framework
INFO[0015] arch: aarch64
INFO[0015] runtime: docker
INFO[0015] mountType: virtiofs
INFO[0015] address: 192.168.107.2
INFO[0015] socket: unix:///Users//.colima/default/docker.sock
```

### Reproduction Steps

1. Create a template or do `colima start --edit`
2. Update the runtime key to:
```yaml
runtime: incus
```
3. Observe that the VM starts with a `docker` runtime

### Expected behaviour

The VM should start with `incus` runtime.

### Additional context

Passing `--runtime incus` does work, however.