FIX: fix installer

install_python_client.sh

@@ -5,8 +5,7 @@ dir_name="temp_dir"
 default_api_url="https://gitlab.indiscale.com/fdo/fdo-manager-service/-/raw/main/api/src/main/resources/api.yaml"
 
 # Check openapi-python-client and install if necessary
-if [ "$(which openapi-python-client)" == "" ]
-then
+if [ -z "$(which openapi-python-client)" ]; then
   echo 'openapi-python-client not found, installing'
   pip install openapi-python-client
 fi