remove fail_ci_if_error: false to surface upload failures

Per review feedback — keep CI failing on Codecov upload errors
so broken coverage is caught immediately, not months later.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: ptomanRH

.github/workflows/codecov.yaml

@@ -83,4 +83,3 @@ jobs:
           flags: unit-tests
           files: codecov.json
           slug: guacsec/trustify
-          fail_ci_if_error: false