mw.ViewPageTarget.init: Add missing "accesskey-ca-editsource" message

Added the wrong one, message "accesskey-ca-ve-editsource"
doesn't even exist. It worked locally but that was probably
a lucky race condition or cache.

Follows-up 10fd1a3, b21fe5f.

Bug: 50725
Change-Id: Ie87f8c6861dfe010c038ddb103aa5ea56cd57d24
Merge "mw.ViewPageTarget.init: Add missing "accesskey-ca-editsource" message"