Remove dir=auto from firstHeading

Remove dir=auto from firstHeading

dir="auto" was added in r105854 and r105870.
It happens to be useful for completely left-to-right titles
in right-to-left wikis, but time and again the users complain
about titles that are generally right-to-left, but begin with
a left-to-right character, such as
https://fa.wikipedia.org/wiki/3GP_%D9%88_3G2

This seems to cause more problems than it resolves.
Some day we may have proper direction for titles.
Until then we should probably go back to just displaytitle.

Bug: T51093
Change-Id: Ibf408bc6c5d2f8c05667107a547b0b02e06de270