### Godot version

4.01

### System information

Windows 10

### Issue description

It seems a tiles Custom Data is cleared/not set when "Local to Scene" is enabled for the TileMap in the Resource section. At least the custom data isn't set by the time of the _ready function in the script attached to the TileMap.

### Steps to reproduce

create TileMap and tileset with custom data and attached script. in _ready method attempt to read custom data from a used cell. 

In Attached project run it. It will print_debug if it found custom data or not. "Local to Scene" is enabled so it will not find the custom data.

### Minimal reproduction project

[TileMapCustomDataLocalBugReproduce.zip](https://github.com/godotengine/godot/files/11470771/TileMapCustomDataLocalBugReproduce.zip)

}
				return true;
			}
			return false;
		} else if (components.size() == 1 && components[0].begins_with("pattern_") && components[0].trim_prefix("pattern_").is_valid_int()) {
			int pattern_index = components[0].trim_prefix("pattern_").to_int();
			for (int i = patterns.size(); i <= pattern_index; i++) {
				add_pattern(p_value);
			}
			return true;
		}
#ifndef DISABLE_DEPRECATED
	}
#endif 
	return false;
}
bool TileSet::_get(const StringName &p_name, Variant &r_ret) const {
	Vector<String> components = String(p_name).split("/", true, 2);
	if (components.size() == 2 && components[0].begins_with("occlusion_layer_") && components[0].trim_prefix("occlusion_layer_").is_valid_int()) {
		
		int index = components[0].trim_prefix("occlusion_layer_").to_int();
		if (index < 0 || index >= occlusion_layers.size()) {
			return false;
		}
		if (components[1] == "light_mask") {
			r_ret = get_occlusion_layer_light_mask(index);
			return true;
		} else if (components[1] == "sdf_collision") {
			r_ret = get_occlusion_layer_sdf_collision(index);
			return true;