[sean0407]

Issue #, if available: #1715

Description of changes:

gha_build.sh now stops when the archetype's mvn -q clean install command fails, instead of continuing to generate an archetype project with a potentially stale installed artifact. The regression fixture makes that Maven command return 23 and verifies the script exits unsuccessfully before archetype:generate runs.

Checks run:

• bash tests/gha_build_archetype_failure_test.sh (network blocked; passed)
• bash -n gha_build.sh tests/gha_build_archetype_failure_test.sh (passed)
• git diff --check HEAD^ HEAD (passed)
• patch_policy.py (2 files, 61 lines; passed)

By submitting this pull request:

• I confirm that my contribution is made under the terms of the Apache 2.0 license.
• I confirm that I've made a best effort attempt to update all relevant documentation. No documentation changes were needed for this build-script error-handling fix.