Fix assert due to incorrect format being used in listctrl sample.

"%d" can't be used with long wxListEvent::GetIndex() value in 64 bit builds.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@75189 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Update the URL of the web site images used in the test.

The old images don't exist any more after web site redesign.

Also, the new favicon can't be loaded from an unseekable stream because it
contains multiple icons, so point to the old favicon instead.

Closes #16049.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76089 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775