debug: test epub3-to-pef without --output-file-format to isolate issue

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Author: taylorarndt

.github/workflows/build-epub.yml

@@ -62,8 +62,7 @@ jobs:
           pipeline2/daisy-pipeline/cli/dp2 epub3-to-pef \
             --source "$(pwd)/epub/git-going-with-github.epub" \
             --data /tmp/tts-config.xml \
-            --output "$(pwd)/epub/brf/" \
-            --output-file-format "(-daisy-locale: en-US)" || echo "BRF conversion failed - check dp2 logs above"
+            --output "$(pwd)/epub/brf/" || echo "BRF conversion failed - check dp2 logs above"
           ls epub/brf/ || echo "No BRF output produced"
 
       - name: Upload EPUB artifact