### Godot version

v4.0.beta.custom_build [fab9926a9]

### System information

Fedora 37

### Issue description

When creating a new inherited scene, saving the scene (for example with Ctrl+S) defaults to overwriting the scene being inherited, instead of prompting for a location to save to.

### Steps to reproduce

1. Create a new inherited scene
2. Press Ctrl+S

If the scene being inherited is imported (for example from a glTF), an error displays. If the inherited scene is a .tscn or .scn, it gets overridden by an inherited scene that tries to inherit itself, which is impossible and thus corrupt.

### Minimal reproduction project

N/A
index_sets.write[scene_name_to_set_index[scene_name]].insert(i);
	}
	
	for (int i = 0; i < index_sets.size(); i++) {
		RBSet<int> iset = index_sets[i];
		while (iset.size() > 1) {
			
			for (const int &E : iset) {
				int set_idx = E;
				String scene_name = r_filenames[set_idx];
				String full_path = p_full_paths[set_idx];
				
				scene_name = scene_name.get_basename();
				if (full_path.begins_with("res:")) {
					full_path = full_path.substr(6);
				}
				full_path = full_path.get_basename();
				
				scene_name = scene_name.trim_suffix("/");
				full_path = full_path.trim_suffix("/");
				int scene_name_size = scene_name.size();
				int full_path_size = full_path.size();
				int difference = full_path_size - scene_name_size;
				
				
				
				
				if (difference > 0) {
					String parent = full_path.substr(0, difference);
					int slash_idx = parent.rfind("/");