### Godot version

v4.0.3.stable.mono.official [5222a99f5]

### System information

macOS Monterey 12.6.6 (21G646)

### Issue description

When creating a tileset by code with custom data layers, removing a layer with `remove_custom_data_layer` does not update the name-to-layer mapping; `get_custom_data_layer_by_name` will continue to return that layer's original index.

This has a downstream effect of causing TileData objects attempting to use `get_custom_data('Layer B')` to return invalid data (whatever custom data is now in Layer B's old index; e.g. Layer C).

I would expect that after using `remove_custom_data_layer`, I would be able to still use `get_custom_data_layer_by_name` on that tileset.

### Steps to reproduce

Run this code to see that getting Layer B by name after removing the first layer continues to return its original index (1) when in reality it is now at index 0.
```
	var tileset:TileSet = TileSet.new()

	tileset.add_custom_data_layer()
	tileset.set_custom_data_layer_name(0, 'Layer A')
	tileset.set_custom_data_layer_type(0, TYPE_INT)

	tileset.add_custom_data_layer()
	tileset.set_custom_data_layer_name(1, 'Layer B')
	tileset.set_custom_data_layer_type(1, TYPE_STRING)

	print('Layer index 0 name : ', tileset.get_custom_data_layer_name(0)) # Layer A
	print('Layer index 1 name : ', tileset.get_custom_data_layer_name(1)) # Layer B
	print('Layer B is on index : ', tileset.get_custom_data_layer_by_name("Layer B")) # 1

	print('----- removing custom data layer 0 -----')
	tileset.remove_custom_data_layer(0)

	print('Layer index 0 name : ', tileset.get_custom_data_layer_name(0)) # Layer B
	print('Layer index 1 name : ', tileset.get_custom_data_layer_name(1)) # prints an error, as expected
	print('Layer B is on index : ', tileset.get_custom_data_layer_by_name("Layer B")) # returns 1 still! should return 0.
```

### Minimal reproduction project

[RemoveCustomDataLayer.zip](https://github.com/godotengine/godot/files/11804762/RemoveCustomDataLayer.zip)

}
		}
		terrain_bits_meshes_dirty = false;
	}
	int terrain_set = p_tile_data->get_terrain_set();
	if (terrain_set < 0) {
		return;
	}
	TileSet::TerrainMode terrain_mode = get_terrain_set_mode(terrain_set);
	RenderingServer::get_singleton()->canvas_item_add_set_transform(p_canvas_item->get_canvas_item(), p_transform);
	int terrain_id = p_tile_data->get_terrain();
	if (terrain_id >= 0) {
		Color color = get_terrain_color(terrain_set, terrain_id);
		color.a = TERRAIN_ALPHA;
		p_canvas_item->draw_mesh(terrain_meshes[terrain_mode], Ref<Texture2D>(), Transform2D(), color);
	}
	for (int i = 0; i < TileSet::CELL_NEIGHBOR_MAX; i++) {
		CellNeighbor bit = CellNeighbor(i);
		if (is_valid_terrain_peering_bit(terrain_set, bit)) {
			terrain_id = p_tile_data->get_terrain_peering_bit(bit);
			if (terrain_id >= 0) {
				Color color = get_terrain_color(terrain_set, terrain_id);
				color.a = TERRAIN_ALPHA;
				p_canvas_item->draw_mesh(terrain_peering_bits_meshes[terrain_mode][bit], Ref<Texture2D>(), Transform2D(), color);
			}
		}
	}
	RenderingServer::get_singleton()->canvas_item_add_set_transform(p_canvas_item->get_canvas_item(), Transform2D());
}
Vector<Vector<Ref<Texture2D>>> TileSet::generate_terrains_icons(Size2i p_size) {