bam2egg: change overloaded method (for ABI reasons) to default arg

This is a follow-up to ebd538a7f83bd4ff9938a7e5f97a9ad8e6198552

panda/src/egg2pg/eggSaver.cxx

@@ -339,15 +339,6 @@ convert_anim_node(AnimBundleNode *node, const WorkingNodePath &node_path,
   eggTable->add_child(eggAnimation);
 }
 
-/**
- * Converts the indicated Character Bundle to the corresponding Egg joints
- * structure.
- */
-void EggSaver::
-convert_character_bundle(PartGroup *bundleNode, EggGroupNode *egg_parent, CharacterJointMap *joint_map) {
-  convert_character_bundle(bundleNode, egg_parent, joint_map, nullptr);
-}
-
 /**
  * Converts the indicated Character Bundle to the corresponding Egg joints
  * structure.

panda/src/egg2pg/eggSaver.h

@@ -77,10 +77,9 @@ private:
                         EggGroupNode *egg_parent, bool has_decal);
   void convert_character_node(Character *node, const WorkingNodePath &node_path,
                         EggGroupNode *egg_parent, bool has_decal);
-  void convert_character_bundle(PartGroup *bundleNode, EggGroupNode *egg_parent, CharacterJointMap *jointMap);
   void convert_character_bundle(PartGroup *bundleNode, EggGroupNode *egg_parent,
                                 CharacterJointMap *jointMap,
-                                const CharacterJoint *parent_joint);
+                                const CharacterJoint *parent_joint = nullptr);
   void convert_collision_node(CollisionNode *node, const WorkingNodePath &node_path,
                               EggGroupNode *egg_parent, bool has_decal,
                               CharacterJointMap *joint_map);