HuggingFace Space template for Label Studio uses the wrong host parameter

In the default template space for launching Label Studio on HuggingFace Spaces, it has the following launch command:

```
CMD exec label-studio --host=$SPACE_HOST
```

However, `host` expects a protocol like `https://` and `SPACE_HOST` is just the hostname (`org-space.hf.space`). Everything loads up correctly but this bug makes it impossible to access the space via API calls as needed by the sdk (i.e. through `https://org-space.hf.space`)

I manually changed this in my forked space and everything worked as desired so I think this just requires changing the template docker file on HuggingFace.