ENH: config: refine some small logic

1. always resize filament count when not matched in full_fff_print
2. remove no-use codes in Preset::normalize

jira: no-jira
Change-Id: Ie15a5977d28f28e0f63ba84f27f98f77d16665c0
(cherry picked from commit f122c4f4ef6f476c4e8190a0872e566d690d6c25)

src/libslic3r/PresetBundle.cpp

@@ -2173,7 +2173,8 @@ DynamicPrintConfig PresetBundle::full_fff_config(bool apply_extruder, std::vecto
     // BBS
     size_t  num_filaments = this->filament_presets.size();
 
-    if (filament_maps.empty()) {
+    //in some middle state, they may be different
+    if (filament_maps.size() != num_filaments) {
         filament_maps.resize(num_filaments, 1);
     }