[Docs]: Include "npm install" in build steps for GitLab Pages deploy docs

[S4GU4R0]

Request Type

Explanation Improvement (make a description clearer for the reader of the docs)

Description

When trying to deploy to GitLab Pages, I followed these steps very literally, too literally, and didn't realize npm install was assumed. This sent me down an unrelated rabbit hole, since the error it gives is obvious once you realize what happened but less so if you don't realize what happened. I'd like to save someone else the time I spent. Mostly submitting this issue to get permission to add the fix myself really quick. Thanks!

Are you interested in contributing this improvement to the docs?

I'd like to contribute, and I'll open a PR

[archiewood]

looking at the docs today, this is already included

the install step is npm ci and included above the build step