Throw exception if release is found but no files are included

[shahiddev]

Describe the bug
We had an example where downloading the release didn't download any files but the action thought everything was sweet

To Reproduce
Can't repro - likely issue with GH API or some kind of eventual consistency/race condition

Expected behaviour
If downloading a release and no files are found in the release throw an exception

Additional context
It looks like we could tweak the handling of release downloads to warn/throw if a release is found but no files are found in it.
Happy to take a look at doing a PR if that would help - thinking we could tweak the if statement here