chore: fail when one of the two fronend scripts fail

Signed-off-by: Ferdinand Thiessen <opensource@fthiessen.de>

build/demi.sh

@@ -30,7 +30,10 @@ run_sequentially() {
 	echo -e "\e[1;34m>> Running 'npm $COMMAND' for Vue 3 based frontend\e[0m"
 	echo
 	pushd "$FRONTEND"
+	set +e
 	npm $COMMAND
+	STATUS=$?
+	set -e
 	popd
 
 	echo -e "\e[1;34m>> Running 'npm $COMMAND' for Vue 2 based frontend\e[0m"
@@ -38,9 +41,14 @@ run_sequentially() {
 	pushd "$FRONTEND_LEGACY"
 	npm $COMMAND
 	popd
-}
 
+	if [ $STATUS -ne 0 ]; then
+		echo -e "\e[1;31m>> Vue 3 based frontend build failed\e[0m"
+		exit $STATUS
+	fi
+}
 
+set -e
 if [ "--parallel" = "$1" ]; then
 	build_command ${@:2}
 	run_parallel