The new instance starts up from fallback, while still downloading the image

### Description

For some templates, we define one "snapshot" version with a date and one "latest" version without one:

https://github.com/lima-vm/lima/blob/master/examples/ubuntu-lts.yaml

So it is common to have an old versioned releases, and an old (static) latest release image laying around...

When I was starting a new instance, it begun to download the new snapshot - and then started the old fallback

```
$ limactl start template://apptainer
? Creating an instance "apptainer" Proceed with the current configuration
INFO[0002] Attempting to download the image arch=x86_64 digest="sha256:d5b419272e01cd69bfc15cbbbc5700d2196242478a54b9f19746da3a1269b7c8" location="https://cloud-images.ubuntu.com/releases/22.04/release-20230729/ubuntu-22.04-server-cloudimg-amd64.img"
Downloading the image (ubuntu-22.04-server-cloudimg-amd64.img)
207.56 MiB / 656.31 MiB [----------->_______________________] 31.63% 13.07 MiB/sINFO[0018] Attempting to download the image arch=x86_64 digest= location="https://cloud-images.ubuntu.com/releases/22.04/release/ubuntu-22.04-server-cloudimg-amd64.img"
208.39 MiB / 656.31 MiB [----------->_______________________] 31.75% 12.91 MiB/sINFO[0019] Using cache "/home/anders/.cache/lima/download/by-url-sha256/6b15519b255a45a238b7a8154cd57da120344ea388143af2821bb790af7fc587/data"
208.39 MiB / 656.31 MiB [----------->_______________________] 31.75% 12.91 MiB/sINFO[0019] [hostagent] Starting QEMU (hint: to watch the boot progress, see "/home/anders/.lima/apptainer/serial*.log")
```

You can see that the download progress bar gets confused, and mixed up with the log from the start.

Maybe it needs a better way to specify the fallback, instead of just having both of them in an array like now ?

Using `limactl create template://apptainer` also avoids the situation, but that is not what is currently [documented](https://apptainer.org/docs/admin/1.2/installation.html#id3).