### 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)

(source_id != TileSet::INVALID_SOURCE || atlas_coords != TileSetSource::INVALID_ATLAS_COORDS || alternative_tile != TileSetSource::INVALID_TILE_ALTERNATIVE)) {
		source_id = TileSet::INVALID_SOURCE;
		atlas_coords = TileSetSource::INVALID_ATLAS_COORDS;
		alternative_tile = TileSetSource::INVALID_TILE_ALTERNATIVE;
	}
	if (!E) {
		if (source_id == TileSet::INVALID_SOURCE) {
			return; 
		}
		
		CellData new_cell_data;
		new_cell_data.coords = pk;
		E = tile_map.insert(pk, new_cell_data);
	} else {
		if (E->value.cell.source_id == source_id && E->value.cell.get_atlas_coords() == atlas_coords && E->value.cell.alternative_tile == alternative_tile) {
			return; 
		}
	}
	TileMapCell &c = E->value.cell;
	c.source_id = source_id;
	c.set_atlas_coords(atlas_coords);
	c.alternative_tile = alternative_tile;
	
	if (!E->value.dirty_list_element.in_list()) {
		dirty.cell_list.add(&(E->value.dirty_list_element));
	}
	tile_map_node->queue_internal_update();
	used_rect_cache_dirty = true;
}
void TileMapLayer::erase_cell(const Vector2i &p_coords) {