Disable MediaViewer by default for logged-in users on Commons

Soft-depends on Ief0df5b4f4285d99208f007b0510a396f6c272e0

Bug: 69363
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/822
Change-Id: I90f6ab5b44fbcde0b89f56e795f69472c4940854
Merge "Disable MediaViewer by default for logged-in users on Commons"