### 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)

Ref<Image> image = Image::create_empty(size.x, size.y, false, src->get_format());
	for (KeyValue<Vector2i, TileAlternativesData> kv : tiles) {
		for (int frame = 0; frame < (int)kv.value.animation_frames_durations.size(); frame++) {
			
			Rect2i src_rect = get_tile_texture_region(kv.key, frame);
			Rect2i top_src_rect = Rect2i(src_rect.position, Vector2i(src_rect.size.x, 1));
			Rect2i bottom_src_rect = Rect2i(src_rect.position + Vector2i(0, src_rect.size.y - 1), Vector2i(src_rect.size.x, 1));
			Rect2i left_src_rect = Rect2i(src_rect.position, Vector2i(1, src_rect.size.y));
			Rect2i right_src_rect = Rect2i(src_rect.position + Vector2i(src_rect.size.x - 1, 0), Vector2i(1, src_rect.size.y));
			
			Vector2i frame_coords = kv.key + (kv.value.size_in_atlas + kv.value.animation_separation) * ((kv.value.animation_columns > 0) ? Vector2i(frame % kv.value.animation_columns, frame / kv.value.animation_columns) : Vector2i(frame, 0));
			Vector2i base_pos = frame_coords * (texture_region_size + Vector2i(2, 2)) + Vector2i(1, 1);
			image->blit_rect(*src, src_rect, base_pos);
			image->blit_rect(*src, top_src_rect, base_pos + Vector2i(0, -1));
			image->blit_rect(*src, bottom_src_rect, base_pos + Vector2i(0, src_rect.size.y));
			image->blit_rect(*src, left_src_rect, base_pos + Vector2i(-1, 0));
			image->blit_rect(*src, right_src_rect, base_pos + Vector2i(src_rect.size.x, 0));
			image->set_pixelv(base_pos + Vector2i(-1, -1), src->get_pixelv(src_rect.position));
			image->set_pixelv(base_pos + Vector2i(src_rect.size.x, -1), src->get_pixelv(src_rect.position + Vector2i(src_rect.size.x - 1, 0)));
			image->set_pixelv(base_pos + Vector2i(-1, src_rect.size.y), src->get_pixelv(src_rect.position + Vector2i(0, src_rect.size.y - 1)));
			image->set_pixelv(base_pos + Vector2i(src_rect.size.x, src_rect.size.y), src->get_pixelv(src_rect.position + Vector2i(src_rect.size.x - 1, src_rect.size.y - 1)));
		}
	}
	if (!padded_texture.is_valid()) {
		padded_texture.instantiate();
	}
	padded_texture->set_image(image);
	emit_changed();
}
void TileSetScenesCollectionSource::_compute_next_alternative_id() {