### 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_MSG(p_coords.x < 0 || p_coords.y < 0, vformat("Cannot set cell with negative coords in a TileMapPattern. Wrong coords: %s", p_coords));
	size = size.max(p_coords + Vector2i(1, 1));
	pattern[p_coords] = TileMapCell(p_source_id, p_atlas_coords, p_alternative_tile);
	emit_changed();
}
bool TileMapPattern::has_cell(const Vector2i &p_coords) const {
	return pattern.has(p_coords);
}
void TileMapPattern::remove_cell(const Vector2i &p_coords, bool p_update_size) {
	ERR_FAIL_COND(!pattern.has(p_coords));
	pattern.erase(p_coords);
	if (p_update_size) {
		size = Size2i();
		for (const KeyValue<Vector2i, TileMapCell> &E : pattern) {
			size = size.max(E.key + Vector2i(1, 1));
		}
	}
	emit_changed();
}
int TileMapPattern::get_cell_source_id(const Vector2i &p_coords) const {