Make message clearer for two-factor authentication error

Make an error message crealer in app/controllers/repositories/git_http_client_controller.rb in def ender_access_denied and change from:

"HTTP Basic: Access denied. The provided password or token is incorrect or your account has 2FA enabled and you must use a personal access token instead of a password. See %{help_page_url}"

to

"HTTP Basic: Access denied. You must use a token instead of a password to authenticate for git, or the provided token is incorrect or expired or improperly scoped. See %{help_page_url}"