Describe the bug
If you upload a schema which is not valid (i.e. does not compile), then the check in Apollo Studio will fail, but the GHA will pass with no indication. I encountered this in particular from federation version upgrade errors on Apollo.

This only occurs if alwaysComment is not set.

To Reproduce
Steps to reproduce the behavior:

1. Change your schema by setting a scalar to a non-sensical name for instance
2. Run the action against the new schema
3. Observe the check passes.
4. But look in Apollo studio and notice the check fails with build errors

Expected behavior
The GHA should fail any time the Apollo Studio check fails. Otherwise it's possible for silent breakages.

Additional context
I will provide a PR for this shortly!