fix: expand glob before checking API count in join

[NeelChotai]

What/Why/How?

Fixes https://github.com/Redocly/redocly-cli/issues/1196.

Reference

Testing

Tested locally in /bin/sh env and works where it was previously failing.

Screenshots (optional)

Check yourself

• [x] Code changed? - Tested with redoc/reference-docs/workflows (internal)
• [x] All new/updated code is covered with tests

Security

• [x] Security impact of change has been considered
• [x] Code follows company security practices and guidelines