npm install, ports and poudriere

Hello,

I made a port of MongoDB Compass https://www.mongodb.com/docs/compass/current/ .
As it is an electron app, I need to use "npm install" to build it.

npm install does not work without network connection, while poudriere
allow network connection only at fetch time.
As a result, I need to do bunch of things in fetch mode, and the
Makefile became as attached. Is this acceptable as a port?
If not, I need to rework the Makefile to do npm install at build time,
but that makes the port not officially buildable I think. (though to
each of us, there is ALLOW_NETWORKING_PACKAGES option in
poudriere.conf)