### 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(p_margins.x < 0 || p_margins.y < 0, PackedVector2Array());
	ERR_FAIL_COND_V(p_separation.x < 0 || p_separation.y < 0, PackedVector2Array());
	ERR_FAIL_COND_V(p_texture_region_size.x <= 0 || p_texture_region_size.y <= 0, PackedVector2Array());
	
	Size2 new_grid_size;
	if (p_texture.is_valid()) {
		Size2i valid_area = p_texture->get_size() - p_margins;
		
		if (valid_area.x >= p_texture_region_size.x && valid_area.y >= p_texture_region_size.y) {
			valid_area -= p_texture_region_size;
			new_grid_size = Size2i(1, 1) + valid_area / (p_texture_region_size + p_separation);
		}
	}
	Vector<Vector2> output;
	for (KeyValue<Vector2i, TileAlternativesData> &E : tiles) {
		for (unsigned int frame = 0; frame < E.value.animation_frames_durations.size(); frame++) {
			Vector2i frame_coords = E.key + (E.value.size_in_atlas + E.value.animation_separation) * ((E.value.animation_columns > 0) ? Vector2i(frame % E.value.animation_columns, frame / E.value.animation_columns) : Vector2i(frame, 0));
			frame_coords += E.value.size_in_atlas;
			if (frame_coords.x > new_grid_size.x || frame_coords.y > new_grid_size.y) {
				output.push_back(E.key);
				break;
			}
		}
	}
	return output;
}
Rect2i TileSetAtlasSource::get_tile_texture_region(Vector2i p_atlas_coords, int p_frame) const {