### 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)

for (Vector2i E_coords : p_painted) {
		TileData *tile_data = nullptr;
		TileMapCell cell = get_cell(E_coords);
		if (cell.source_id != TileSet::INVALID_SOURCE) {
			Ref<TileSetSource> source = tile_set->get_source(cell.source_id);
			Ref<TileSetAtlasSource> atlas_source = source;
			if (atlas_source.is_valid()) {
				tile_data = atlas_source->get_tile_data(cell.get_atlas_coords(), cell.alternative_tile);
			}
		}
		int terrain = (tile_data && tile_data->get_terrain_set() == p_terrain_set) ? tile_data->get_terrain() : -1;
		if (!p_ignore_empty_terrains || terrain >= 0) {
			constraints.insert(TerrainConstraint(tile_map_node, E_coords, terrain));
		}
	}
	return constraints;
}
void TileMapLayer::set_tile_map(TileMap *p_tile_map) {
	tile_map_node = p_tile_map;
}
void TileMapLayer::set_layer_index_in_tile_map_node(int p_index) {
	if (p_index == layer_index_in_tile_map_node) {
		return;
	}
	layer_index_in_tile_map_node = p_index;
	dirty.flags[DIRTY_FLAGS_LAYER_INDEX_IN_TILE_MAP_NODE] = true;
	tile_map_node->queue_internal_update();
}
Rect2 TileMapLayer::get_rect(bool &r_changed) const {