Change m.wikipedia.org check pattern again

The "Last modified on" as proposed by mobile doesn't (always?) appear on
the footer of en.m's main page ("View edit history of this page" is
being used instead). Switch to "Terms of Use" as an emergency fix,
although I start to doubt the usefulness of this check in general and
why mobile is different than desktop in this case...

Change-Id: I31dc6c7ab76cca25c5844c28bc238e741c9aaf99