RESTRICT AUTOMERGE

Do not set referrerUri on SessionInfo for non-owners

This change leaves the referrerUri field null when the caller leading to
its production is not the owner of the session.

Bug: 142125338
Test: atest SessionReferrerUriTest
Change-Id: I84679ea0636aa2097e25e23813c48134c9cc1d75
(cherry picked from commit 681b2364)