Fix rename animation in SpriteFramesEditor

[Rindbee]

When the name suffix grows, the old name is used if it is obtained first.

Fix the case where the following error message would appear when renaming an animation.

ERROR: Animation '' doesn't exist.
   at: get_frame_count (scene/resources/sprite_frames.cpp:71)

Fix #73883.

[TokageItLab]

To be honest, I don't really remember what this initialization was implemented for. The _rename_node_animation() is a method to change the animation name kept in other properties of AnimatedSprite, but without it, it is possible to have some inconsistencies in some properties, so it should be tested carefully.

[Rindbee]

The previous code will rename name to a non-empty value. Even though it would have side effects, I feel like it could be done in the call on line 961.

godot/editor/plugins/sprite_frames_editor_plugin.cpp

Lines 958 to 962 in 57919be

	_rename_node_animation(undo_redo, false, edited_anim, "", "");
	undo_redo->add_do_method(frames.ptr(), "rename_animation", edited_anim, name);
	undo_redo->add_undo_method(frames.ptr(), "rename_animation", name, edited_anim);
	_rename_node_animation(undo_redo, false, edited_anim, name, name);
	_rename_node_animation(undo_redo, true, edited_anim, edited_anim, edited_anim);

godot/editor/plugins/sprite_frames_editor_plugin.cpp

Lines 971 to 973 in 57919be

	void SpriteFramesEditor::_rename_node_animation(EditorUndoRedoManager *undo_redo, bool is_undo, const String &p_filter, const String &p_new_animation, const String &p_new_autoplay) {
	List<Node *> nodes;
	_find_anim_sprites(EditorNode::get_singleton()->get_edited_scene(), &nodes, Ref<SpriteFrames>(frames));

[TokageItLab]

I don't know what affect deleting the _rename_node_animation(undo_redo, false, edited_anim, "", ""); would have. Perhaps it was there to prevent some error when trying to use a space in the name, but rather it seems to be triggering an error and should be removed. If this removing causes other errors, that should be resolved in another way.

Well, I tested this and it seems to work fine, so I believe this can be merged.

[YuriSizov]

Thanks! Don't think we should cherry-pick it into patch releases if we aren't sure what the removal may affect. But we can consider it for 4.1 after some time, if there are no issues reported.

[YuriSizov]

Cherry-picked for 4.1.4.