### 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)

set_cell(p_coords, TileSet::INVALID_SOURCE, TileSetSource::INVALID_ATLAS_COORDS, TileSetSource::INVALID_TILE_ALTERNATIVE);
}
int TileMapLayer::get_cell_source_id(const Vector2i &p_coords, bool p_use_proxies) const {
	
	HashMap<Vector2i, CellData>::ConstIterator E = tile_map.find(p_coords);
	if (!E) {
		return TileSet::INVALID_SOURCE;
	}
	const Ref<TileSet> &tile_set = tile_map_node->get_tileset();
	if (p_use_proxies && tile_set.is_valid()) {
		Array proxyed = tile_set->map_tile_proxy(E->value.cell.source_id, E->value.cell.get_atlas_coords(), E->value.cell.alternative_tile);
		return proxyed[0];
	}
	return E->value.cell.source_id;
}
Vector2i TileMapLayer::get_cell_atlas_coords(const Vector2i &p_coords, bool p_use_proxies) const {
	
	HashMap<Vector2i, CellData>::ConstIterator E = tile_map.find(p_coords);
	if (!E) {
		return TileSetSource::INVALID_ATLAS_COORDS;
	}
	const Ref<TileSet> &tile_set = tile_map_node->get_tileset();
	if (p_use_proxies && tile_set.is_valid()) {
		Array proxyed = tile_set->map_tile_proxy(E->value.cell.source_id, E->value.cell.get_atlas_coords(), E->value.cell.alternative_tile);
		return proxyed[1];
	}
	return E->value.cell.get_atlas_coords();
}
int TileMapLayer::get_cell_alternative_tile(const Vector2i &p_coords, bool p_use_proxies) const {