Improve error messaging for CI_JOB_TOKEN, git repository

Original issue: #439655 (closed)

What does this MR do and why?

The goal of this MR is to improve error messaging when CI_JOB_TOKEN is used to access the git repository.

Instead of presenting abstract error message: The project you were looking for could not be found or you don't have permission to view it.

In case when we get rejected because of CI_JOB_TOKEN permission we will expose the following error: Authentication by CI/CD job token not allowed from %{source_project_path} to %{target_project_path}.

A new error message covers all known requests via CI_JOB_TOKEN to git repository:

1. git clone
2. git pull
3. git fetch

MR acceptance checklist

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Before	After

How to set up and validate locally

Define various of jobs in .gitlab-ci.yml

Configure two projects:

1. git_clone_source_project
2. test_ci_job_token_git_clone

Create a .gitlab-ci.yml file on test_ci_job_token_git_clone with following instructions on the top

stages:
  - git
  - repo_api
  - deployment_api
  - environment_api

variables:
  SOURCE_PROJECT: "dmitry/test_ci_job_token_errors/git_clone_source_project.git"
  SOURCE_PROJECT_ID: "98"
  CURRENT_PROJECT_ID: "97"

clone_repo:
  stage: git
  needs: []
  script:
    - git clone $CI_REPOSITORY_URL
    - cd $CI_PROJECT_NAME
    - git checkout $CI_COMMIT_SHA
  artifacts:
    paths:
      - $CI_PROJECT_NAME
    expire_in: 1 hour

clone_source:
  stage: git
  needs: []
  script:
    - 'git clone http://gitlab-ci-token:${CI_JOB_TOKEN}@${CI_SERVER_HOST}:3000/${SOURCE_PROJECT} source_project'
    - cd source_project
    - git checkout $CI_COMMIT_REF_NAME || git checkout main  # Fallback to main if branch doesn't exist
  artifacts:
    paths:
      - source_project
    expire_in: 1 hour

fetch_source:
  stage: git
  needs: []
  script:
    - mkdir source_project
    - cd source_project
    - git init
    - 'git remote add origin http://gitlab-ci-token:${CI_JOB_TOKEN}@${CI_SERVER_HOST}:3000/${SOURCE_PROJECT}'
    - git fetch origin
    - git checkout $CI_COMMIT_REF_NAME || git checkout main  

pull_source:
  stage: git
  needs: []
  script:
    - mkdir -p source_project
    - cd source_project
    - git init
    - 'git remote add origin http://gitlab-ci-token:${CI_JOB_TOKEN}@${CI_SERVER_HOST}:3000/${SOURCE_PROJECT}'
    - git pull origin $CI_COMMIT_REF_NAME || git pull origin main  # Pull the specified branch or fallback to main
  artifacts:
    paths:
      - source_project
    expire_in: 1 hour

3. Test error message when test_ci_job_token_git_clone is not added to the allow list on git_clone_source_project