Removed variables and #include in EditorSceneImporterAssimp::import_scene that became unused after the recent commit ec1bf96(#39363).
Removed variables and #include in EditorSceneImporterAssimp::import_scene that became unused after the recent commit ec1bf96(#39363).

(cherry picked from commit 365c35f30ea3b4749c8a0ca07db8464f9b6bc41c)

ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot,ex/godot