Update createCheckIndex.php to use Maintenance class

Change-Id: Ia2c714ea5294a17aed5d95399e42b57494750424
Use group source language

Instead of hard coded "en".

Bug: 55607
Change-Id: I6ebb1cfeab3b5c065eb28e6d69a4329b2655b493
Merge changes I6ebb1cfe,Ia2c714ea

* changes:
  Use group source language
  Update createCheckIndex.php to use Maintenance class