Add notice for channel and revision

https://github.com/canonical/inference-snaps-dev/blob/b050d21637b8c4fda364f372938b4f9cb76697fa/actions/publish/action.yml#L53

When a snap is successfully uploaded to the store, snapcraft prints a log line similar to:
```
Revision created for '' and released to '//'
```

It would be useful to add a notice annotation to the workflow to make it easier to find the revision number and track name.

The upload script is generic, and can be called manually. So perhaps inside the action.yaml we can pipe the output of the upload script to `tee`. That way the output is still logged to stdout as it's done currently, but we can also capture it in a file/variable. We can then grep through the file/var to find the line containing the revision and release, exposing those two as outputs of the action. The user can then decide if they want to add a notice for these two variables.