fix: exit with error when create-feature-category-issue fails

What

When triggering the script that fires the curl command to create an issue, it should exit with a non-successful exit code in the the HTTP call response is not successful.

Why

This MR closes #2590 (closed).

An expired token made the pipeline succeed when it shouldn't:

$ scripts/create-feature-category-issue
{"message":"401 Unauthorized"}
Cleaning up project directory and file based variables
Job succeeded

By forcing curl to fail when HTTP response is a failure, the pipeline will fall through, and slack integration will make sure the pipeline failure is reported on g_scalability-observability channel: