Replacing MWTitleInputWidget.getValue() with MWTitleInputWidget.getTitle()

Now that we have .getTitle() as a method in MWTitleInputWidget, replacing the callers
of MWTitleInputWidget.getValue() with .getTitle(). This fixes a bug in the .getTitle()
method in MWTitleInputWidget which was not taking the namespaces into account before.

Also fixes: the error when entering "Talk:" as a template title. The button to add template
remains disabled when "Talk:" is given as an input to the title here.

Bug: 71998
Change-Id: I1e629a61ec8b035d93a4b7acfecab81934019166
Merge "Replacing MWTitleInputWidget.getValue() with MWTitleInputWidget.getTitle()"