### 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)

RBSet<Vector2i> painted_set;
	for (int i = p_coords_array.size() - 1; i >= 0; i--) {
		const Vector2i &coords = p_coords_array[i];
		can_modify_list.push_back(coords);
		can_modify_set.insert(coords);
		painted_set.insert(coords);
	}
	for (Vector2i coords : p_coords_array) {
		
		for (int j = 0; j < TileSet::CELL_NEIGHBOR_MAX; j++) {
			TileSet::CellNeighbor bit = TileSet::CellNeighbor(j);
			if (tile_set->is_valid_terrain_peering_bit(p_terrain_set, bit)) {
				Vector2i neighbor = tile_map_node->get_neighbor_cell(coords, bit);
				if (!can_modify_set.has(neighbor)) {
					can_modify_list.push_back(neighbor);
					can_modify_set.insert(neighbor);
				}
			}
		}
	}
	RBSet<TerrainConstraint> constraints;
	
	for (Vector2i coords : p_coords_array) {
		
		TerrainConstraint c = TerrainConstraint(tile_map_node, coords, p_terrain);
		c.set_priority(10);
		constraints.insert(c);
	}
	for (int i = 0; i < p_coords_array.size() - 1; i++) {