Revert "Constrain redirects to Wikipedia Zero partner-sourced requests."

There was a huge drop in stats after this change, reverting for now to see if this was the cause.

This reverts commit 19594dfe596f95d4ee24e58a51d7c8a2423edda8

Change-Id: If97e0659f7df88b5c93c61fd2b4ddc4b7b7f1398
Merge "Revert "Constrain redirects to Wikipedia Zero partner-sourced requests.""