Fix issue #10971 (#12108)

Sorry had to re-create the PR as I did some chaos in my repo with CLI. xD

Fixes issue https://github.com/OrcaSlicer/OrcaSlicer/issues/10971

Description:
Fix wipe tower filament selection and clean up tool ordering. Added wipe_tower_filament handling to WipeTower2 (store config, mark non-selected tools as “soluble,” and use it in toolchange selection) and ensured the configured wipe‑tower extruder is included in the extruder list for ordering. Removed duplicated/merged tool‑ordering code (extra insert_wipe_tower_extruder definition, duplicate declaration, and redundant reorder block) so the tool order logic runs only once.

<img width="1819" height="799" alt="image" src="https://github.com/user-attachments/assets/cef39026-cf6a-46da-a87a-ef895774699f" />

src/libslic3r/Print.cpp

@@ -520,6 +520,12 @@ std::vector<unsigned int> Print::extruders(bool conside_custom_gcode) const
         }
     }
 
+    // If a wipe tower filament is explicitly set, ensure it participates in tool ordering.
+    if (has_wipe_tower() && config().wipe_tower_filament != 0 && extruders.size() > 1) {
+        assert(config().wipe_tower_filament > 0 && config().wipe_tower_filament < int(config().nozzle_diameter.size()));
+        extruders.emplace_back(config().wipe_tower_filament - 1); // config value is 1-based
+    }
+
     sort_remove_duplicates(extruders);
     return extruders;
 }