Always add libwxscintilla in monolithic mode.

The library was already present in the makefiles but came before the
monolithic library itself, which broke the linking of the samples when using
GNU ld as the dependent libraries must come after the libraries using them.

Closes #13837.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@74408 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775