### 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)

struct Count {
		int count = 0;
		float probability = 0.0;
		Ref<Texture2D> texture;
		Rect2i region;
	};
	Vector<Vector<Ref<Texture2D>>> output;
	LocalVector<LocalVector<Count>> counts;
	output.resize(get_terrain_sets_count());
	counts.resize(get_terrain_sets_count());
	for (int terrain_set = 0; terrain_set < get_terrain_sets_count(); terrain_set++) {
		output.write[terrain_set].resize(get_terrains_count(terrain_set));
		counts[terrain_set].resize(get_terrains_count(terrain_set));
	}
	for (int source_index = 0; source_index < get_source_count(); source_index++) {
		int source_id = get_source_id(source_index);
		Ref<TileSetSource> source = get_source(source_id);
		Ref<TileSetAtlasSource> atlas_source = source;
		if (atlas_source.is_valid()) {
			for (int tile_index = 0; tile_index < source->get_tiles_count(); tile_index++) {
				Vector2i tile_id = source->get_tile_id(tile_index);
				for (int alternative_index = 0; alternative_index < source->get_alternative_tiles_count(tile_id); alternative_index++) {
					int alternative_id = source->get_alternative_tile_id(tile_id, alternative_index);
					TileData *tile_data = atlas_source->get_tile_data(tile_id, alternative_id);
					int terrain_set = tile_data->get_terrain_set();