Add check for api endpoint for private repo
    
    The check in api endpoint to fetch tags of a repo, a condition is
    introducet keeping the nature of the request as 'GET' and test case is
    written accordingly.
    
    Basically to fetch tag of a private user user needs to be logged in. If
    not then the is_repo_condition will fail and no projects will be
    returned.
    
    A new error code needs to be introduced since now we have projecsts
    which can or cannot be accessible to the user.