Allow job tokens to access internal packages

🌳 What does this MR do and why?

Packages should be accessible from internal projects if you are a logged in user. Currently, they are if you are using a personal access token, but CI_JOB_TOKENs fail.

The reason they fail is explained in this MR description where we fixed the same problem for public projects. The short version is the job token checks the :build_read_project permission rather than the :read_project permission.

So in this MR, we update the :build_read_project permission to allow internal project access, which then also allows for internal package access.

📸 Screenshots or screen recordings

Installing a package from an internal project with a CI_JOB_TOKEN used by a user not a member of the internal project

Before change	After change

💻 How to set up and validate locally

To test, you will need to have gitlab-runner working locally with your GDK or development setup.

1. Create a project (I will call it the package project here) and set it's visibility to internal
2. Publish a package to the package project. I suggest an npm package by following the npm docs.
3. Create a new user. It is important that this user is not a member of the package project.
4. While logged in as the new user, create a separate project (I will call it the CI project here)
5. In the CI project, add a .gitlab-ci.yml file to install the package. For npm, this can be:

   image: node:latest
   
   stages:
     - deploy
   
   deploy:
     stage: deploy
     script:
       - npm config set -- '//127.0.0.1:3000/api/v4/projects/26/packages/npm/:_authToken' "${CI_JOB_TOKEN}"
       - npm config set @foo:registry http://127.0.0.1:3000/api/v4/projects/26/packages/npm/
       - npm install @foo/stuff

   Be sure to update the package name and project ID with your values. My project is ID 26 and my package is @foo/stuff
6. Let the job run, it should be successful.

If you'd like to see the failure scenario, revert the line in the project_policy.rb file. Rerunning the pipeline should result in a failure, where the npm install command receives a 404.

🛃 MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #333444 (closed)