FIX: update is_info_ready function

jira: [STUDIO-10608]
Change-Id: I068969223e54b1fa2056a0acc80bef87d167942c
(cherry picked from commit 44e068e705742b37513d2ce65c18a41007d4b7d8)

src/slic3r/GUI/Widgets/AMSControl.cpp

@@ -633,6 +633,7 @@ void AMSControl::CreateAmsDoubleNozzle()
     }
     if (m_ext_info.size() <= 1) {
         BOOST_LOG_TRIVIAL(trace) << "vt_slot empty!";
+        assert(0);
         return;
     }
     AMSinfo ext_info;