FIX: Can do switch while printing pause

jira: [STUDIO-9789]
Change-Id: I8d5d2195adcd2cd048d95303f0562f24b696e34e
(cherry picked from commit f3777db02d1ae61ff2ad996bf1dbb6c3aba8a1c3)

src/slic3r/GUI/DeviceManager.cpp

@@ -2764,6 +2764,11 @@ bool MachineObject::is_in_prepare()
     return print_status == "PREPARE";
 }
 
+bool MachineObject::is_in_printing_pause() const
+{
+    return print_status == "PAUSE";
+}
+
 bool MachineObject::is_printing_finished()
 {
     if (print_status.compare("FINISH") == 0