Change the cookie name for valid translation workflow

Instead of cx_sourceLang_targetLang_title pattern, use
cx_title_sourceLang_targetLang pattern so that cookie name
never ends with Token or Session. Solves the edge case of
varnish regex for session cookies.

Followup: I640ebdd8
Bug: T76178
Bug: T85130
Change-Id: Ice95c4739a1a659f16e49a43160a83e32c9f2c4f