### 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)

ERR_FAIL_COND_V_MSG(!tiles.has(p_atlas_coords), Rect2i(), vformat("TileSetAtlasSource has no tile at %s.", String(p_atlas_coords)));
	ERR_FAIL_INDEX_V(p_frame, (int)tiles[p_atlas_coords].animation_frames_durations.size(), Rect2i());
	const TileAlternativesData &tad = tiles[p_atlas_coords];
	Vector2i size_in_atlas = tad.size_in_atlas;
	Vector2 region_size = texture_region_size * size_in_atlas + separation * (size_in_atlas - Vector2i(1, 1));
	Vector2i frame_coords = p_atlas_coords + (size_in_atlas + tad.animation_separation) * ((tad.animation_columns > 0) ? Vector2i(p_frame % tad.animation_columns, p_frame / tad.animation_columns) : Vector2i(p_frame, 0));
	Vector2 origin = margins + (frame_coords * (texture_region_size + separation));
	return Rect2(origin, region_size);
}
bool TileSetAtlasSource::is_position_in_tile_texture_region(const Vector2i p_atlas_coords, int p_alternative_tile, Vector2 p_position) const {