Remove expensive synchronous template validation

Authored by Gilles.


Remove expensive synchronous template validation

In 1.25 the async parameter gets deprecated. This very advanced
feature requires such deep knowledge of how Commons works
that I believe the users who know about it don't really need the
validation. Furthermore, the worst case scenario is just that junk
gets added to a section of the file page's wikitext by a user not
knowing what they're doing. Which doesn't seem like a big deal, since
it can always be fixed after publication.

Change-Id: I6fd8972e9dd9c578d437245598f2d837bd62085d
Mingle: https://wikimedia.mingle.thoughtworks.com/projects/multimedia/cards/854