Synthetic ID Header [X-Psid-Ts] is not being set on /integration re-hosted into first party publisher domain

[jevansnyc]

For example here:

We should properly set the Synthetic ID header on all URL paths under the pub domain, provided the user hasn't opted out via the CMP.

[jevansnyc]

There's also a test "X-Custom-Header" being set here that should be removed.