chore: fix race condition during build.

Author: tbosch

scripts/ci/build_js.sh

@@ -8,4 +8,6 @@ SCRIPT_DIR=$(dirname $0)
 source $SCRIPT_DIR/env_dart.sh
 cd $SCRIPT_DIR/../..
 
-./node_modules/.bin/gulp enforce-format build.js docs
+./node_modules/.bin/gulp enforce-format
+./node_modules/.bin/gulp build.js
+./node_modules/.bin/gulp docs