Fix regression in FBX import caused by Skeleton3D

A change in commit f7fdc87 changed the Skeleton3D "pose" property from PROPERTY_USAGE_EDITOR to PROPERTY_USAGE_NOEDITOR.
This should have had no effect, however it turns out assimp was assigning to the pose property.

This change adjusts the FBX import to only get_bone_rest/set_bone_rest, not set_bone_pose.

modules/assimp/editor_scene_importer_assimp.cpp

@@ -452,7 +452,6 @@ EditorSceneImporterAssimp::_generate_scene(const String &p_path, aiScene *scene,
 				Transform pform = AssimpUtils::assimp_matrix_transform(bone->mNode->mTransformation);
 				skeleton->add_bone(bone_name);
 				skeleton->set_bone_rest(boneIdx, pform);
-				skeleton->set_bone_pose(boneIdx, pform);
 
 				if (parent_node != NULL) {
 					int parent_bone_id = skeleton->find_bone(AssimpUtils::get_anim_string_from_assimp(parent_node->mName));
@@ -626,7 +625,7 @@ void EditorSceneImporterAssimp::_insert_animation_track(ImportState &scene, cons
 				xform.basis.set_quat_scale(rot, scale);
 				xform.origin = pos;
 
-				xform = skeleton->get_bone_pose(skeleton_bone).inverse() * xform;
+				xform = skeleton->get_bone_rest(skeleton_bone).inverse() * xform;
 
 				rot = xform.basis.get_rotation_quat();
 				rot.normalize();