chore: update run_zonal_tests.sh to use google-cloud-python repo and correct directory

Author: zhixiangli

packages/google-cloud-storage/cloudbuild/run_zonal_tests.sh

@@ -4,10 +4,13 @@ echo '--- Installing git and cloning repository on VM ---'
 sudo apt-get update && sudo apt-get install -y git python3-pip python3-venv
 
 # Clone the repository and checkout the specific commit from the build trigger.
-git clone https://github.com/googleapis/python-storage.git
-cd python-storage
-git fetch origin "refs/pull/${_PR_NUMBER}/head"
+git clone https://github.com/googleapis/google-cloud-python.git
+cd google-cloud-python
+if [ -n "${_PR_NUMBER:-}" ]; then
+  git fetch origin "refs/pull/${_PR_NUMBER}/head"
+fi
 git checkout ${COMMIT_SHA}
+cd packages/google-cloud-storage
 
 
 echo '--- Installing Python and dependencies on VM ---'