Issue #3219989: Remove redundant stale logic

Since we have the logic in vcl_error as well as vcl_fetch:

• https://git.drupalcode.org/project/fastly/-/blob/8.x-3.x/vcl_snippets/error.vcl
• https://git.drupalcode.org/project/fastly/-/blob/8.x-3.x/vcl_snippets/fetch.vcl

having this logic in vcl_deliver also with restart doesn't make sense.