Normalise contributor tags to DFP style

This is a bit messy, but we’ve always sent Contributor tags to DFP as
name-lastname. Unfortunately, the Tag id is “profile/nameLastname”, so
we’ll have to do this dance to make it right.
Removed whitespace
Removed stupid debugging
Merge pull request #5459 from guardian/fixingSponsoredContributors

Normalise contributor tags to DFP style