e2e: add test specs for `oras pull` command

[qweeah]

Happy paths:

• should pull all files in an image to a target folder
• should also pull config file with --config option
• should show correct pull status for all the pulling

Bad paths:

• should fail if path traversal is needed but not enabled
• should fail if file overwrite is needed but not enabled
• should fail directly if not logged in
• should fail if no artifact reference provided