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/GCode/ToolOrdering.hpp

@@ -258,6 +258,7 @@ private:
     void				initialize_layers(std::vector<coordf_t> &zs);
     void 				collect_extruders(const PrintObject &object, const std::vector<std::pair<double, unsigned int>> &per_layer_extruder_switches);
     void 				fill_wipe_tower_partitions(const PrintConfig &config, coordf_t object_bottom_z, coordf_t max_layer_height);
+    bool                insert_wipe_tower_extruder();
     void                mark_skirt_layers(const PrintConfig &config, coordf_t max_layer_height);
     void 				collect_extruder_statistics(bool prime_multi_material);
     void                reorder_extruders_for_minimum_flush_volume(bool reorder_first_layer);