RecentChangesLinked: Include title without subpage in form

RecentChangesLinked: Include title without subpage in form

When the 'title' hidden field contains the subpage, the 'target'
input field is never taken into account since the subpage always
takes precedence in ChangesListSpecialPage->setup()

I75cfb2b56a4da6357e6117b3f34f3178bfb2c90c introduced
SpecialRecentChangesLinked->getPageTitle which overrides
SpecialPage->getPageTitle to include the subpage by default.

This helped with redirecting to the right page when parsing
a saved query on the server but changed the behavior everywhere
that function was used in the context of RCL. That includes
SpecialRecentChanges.php:545 where the option form is built.

Bug: T183437
Change-Id: Id39d1887719ecb6900b25fefbb133dff9c4d0456