Compilation fix for wxMSW build with most features disabled.

Include wx/msw/ownerdrawnbutton.h outside of WX_PRECOMP check to ensure it's
always included.

Closes #16380.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76929 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Remove unnecessary ConvertWXArrayToC() helper choice dialog code.

Just use the appropriate wxSingleChoiceDialog ctor directly.

Also some renamings/reformattings, but no other real changes.

Closes #16383.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@76930 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775