Improve container tool detection logic in build.sh for better reliability

build.sh

@@ -4,9 +4,9 @@ IMAGE_NAME="azure-image-chooser"
 #IMAGE="docker.io/skoszewski/$IMAGE_NAME"
 IMAGE="skdomlab.azurecr.io/$IMAGE_NAME"
 
-if [ "$(basename $(command -v docker))" = "docker" ]; then
+if [ ! -z "$(command -v docker)" ] && [ "$(basename $(command -v docker))" = "docker" ]; then
     CMD="docker"
-elif [ "$(basename $(command -v podman))" = "podman" ]; then
+elif [ ! -z "$(command -v podman)" ] && [ "$(basename $(command -v podman))" = "podman" ]; then
     CMD="podman"
 else
     echo "No suitable container tool found"