This reverts commit d29050d080.
Reason for revert: I had mistakenly assumed the @wikimedia/codex
module was loaded on clicking the language button. It appears to
be added on page load.
Given T248718 it's still unclear what our policy on loading
@wikimedia/codex on page load is and given several people are out
I think it would be better to attempt this again next week, possibly
delaying further if needed.
Bug: T353071
Bug: T248718
Change-Id: I09334a1faec06a7400e61013ddda374156bf5d72
5481573341