ENH: config: add the extruder variant apply logic in Print::Apply()

we need to keep the original values and update after pre-slice
jira: no-jira

Change-Id: I232d3c43340b4a23bc42121bd05380746e736f20
(cherry picked from commit 7b7ebf1b959ba5c967baff30fb226c808a2e7d44)

src/libslic3r/PrintBase.hpp

@@ -550,6 +550,7 @@ protected:
 
 	Model                                   m_model;
 	DynamicPrintConfig						m_full_print_config;
+    DynamicPrintConfig						m_ori_full_print_config;  //original full print config without extruder applied
     PlaceholderParser                       m_placeholder_parser;
 
     //BBS: add plate id into print base