### 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)

BIND_ENUM_CONSTANT(TILE_SHAPE_HEXAGON);
	BIND_ENUM_CONSTANT(TILE_LAYOUT_STACKED);
	BIND_ENUM_CONSTANT(TILE_LAYOUT_STACKED_OFFSET);
	BIND_ENUM_CONSTANT(TILE_LAYOUT_STAIRS_RIGHT);
	BIND_ENUM_CONSTANT(TILE_LAYOUT_STAIRS_DOWN);
	BIND_ENUM_CONSTANT(TILE_LAYOUT_DIAMOND_RIGHT);
	BIND_ENUM_CONSTANT(TILE_LAYOUT_DIAMOND_DOWN);
	BIND_ENUM_CONSTANT(TILE_OFFSET_AXIS_HORIZONTAL);
	BIND_ENUM_CONSTANT(TILE_OFFSET_AXIS_VERTICAL);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_RIGHT_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_RIGHT_CORNER);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_BOTTOM_RIGHT_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_BOTTOM_RIGHT_CORNER);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_BOTTOM_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_BOTTOM_CORNER);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_BOTTOM_LEFT_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_BOTTOM_LEFT_CORNER);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_LEFT_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_LEFT_CORNER);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_TOP_LEFT_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_TOP_LEFT_CORNER);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_TOP_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_TOP_CORNER);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_TOP_RIGHT_SIDE);
	BIND_ENUM_CONSTANT(CELL_NEIGHBOR_TOP_RIGHT_CORNER);
	BIND_ENUM_CONSTANT(TERRAIN_MODE_MATCH_CORNERS_AND_SIDES);
	BIND_ENUM_CONSTANT(TERRAIN_MODE_MATCH_CORNERS);
	BIND_ENUM_CONSTANT(TERRAIN_MODE_MATCH_SIDES);
}
TileSet::TileSet() {