Restrict the incoming skylinks to V1 only?

[ro-tex]

If we put the requirement on the caller we can avoid this code here. If we increase the recursive depth of the v2 skylink in the future we will need to remember to update this too. That is probably a good reason to just restrict the scanner to only accept v1 skylinks. The portal should have the v1 skylink anyways by the end of the request. And the scanner won't be scanning before the request completes anyways so we don't lose anything by waiting at the portal level.

The skylink would only not be added if the portal crashed/exited before the request is complete which would mean the user didn't get the full request anyways.

Originally posted by @MSevey in #1 (comment)