### Tested versions

- First reproducible in: v4.2.dev5.official [e3e2528ba]
- Reproducible in: v4.2.stable.official [46dc27791], v4.2.dev5.official [e3e2528ba], v4.2.dev6.official [57a6813bb]
- Not reproducible in: v4.1.3.stable.official [f06b6836a], v4.2.dev1.official [0c2144da9], v4.2.dev2.official [da81ca62a], v4.2.dev3.official [013e8e3af], v4.2.dev4.official [549fcce5f]

### System information

Godot v4.2.stable - Windows 10.0.19045 - Vulkan (Forward+) - dedicated NVIDIA GeForce GTX 1080 (NVIDIA; 31.0.15.4617) - Intel(R) Core(TM) i5-8600K CPU @ 3.60GHz (6 Threads)

### Issue description

The `TileSet` `set_occlusion_layer_light_mask` method does not properly update the `TileSet`'s light mask, causing shadows to still be cast by the `TileSet` even when the light mask is changed using the method to a mask different from a given light source (or even an empty light mask). In v4.1.3.stable.official [f06b6836a] this method was working properly.

### Steps to reproduce

- Download and open the `MRPSetOcclusionLayerTileSet_4.2-stable` project folder using one of the reproducible Godot versions noted above.
- Run the project, and press the spacebar key. This will toggle the occlusion layer light mask value of the on-screen `TileMap`'s `TileSet` occlusion light mask between 0 and 1. You will see that the `TileMap` still casts shadows regardless of the new value of its `TileSets`'s occlusion layer light mask.

### Minimal reproduction project (MRP)

[MRPSetOcclusionLayerTileSetBug.zip](https://github.com/godotengine/godot/files/13592741/MRPSetOcclusionLayerTileSetBug.zip)

Ref<Texture2D> tex = atlas_source->get_runtime_texture();
		if (!tex.is_valid()) {
			return;
		}
		
		Vector2i grid_size = atlas_source->get_atlas_grid_size();
		if (p_atlas_coords.x >= grid_size.x || p_atlas_coords.y >= grid_size.y) {
			return;
		}
		
		const TileData *tile_data = p_tile_data_override ? p_tile_data_override : atlas_source->get_tile_data(p_atlas_coords, p_alternative_tile);
		
		Color modulate = tile_data->get_modulate() * p_modulation;
		
		Vector2 tile_offset = tile_data->get_texture_origin();
		
		Rect2 dest_rect;
		dest_rect.size = atlas_source->get_runtime_tile_texture_region(p_atlas_coords).size;
		dest_rect.size.x += FP_ADJUST;
		dest_rect.size.y += FP_ADJUST;
		bool transpose = tile_data->get_transpose() ^ bool(p_alternative_tile & TileSetAtlasSource::TRANSFORM_TRANSPOSE);
		if (transpose) {
			dest_rect.position = (p_position - Vector2(dest_rect.size.y, dest_rect.size.x) / 2 - tile_offset);
		} else {
			dest_rect.position = (p_position - dest_rect.size / 2 - tile_offset);
		}
		if (tile_data->get_flip_h() ^ bool(p_alternative_tile & TileSetAtlasSource::TRANSFORM_FLIP_H)) {
			dest_rect.size.x = -dest_rect.size.x;
		}