### 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)

const Ref<TileSet> &tile_set = tile_map_node->get_tileset();
	if (!tile_set.is_valid()) {
		return TileSet::TerrainsPattern();
	}
	
	RBMap<TileSet::TerrainsPattern, int> terrain_pattern_score;
	RBSet<TileSet::TerrainsPattern> pattern_set = tile_set->get_terrains_pattern_set(p_terrain_set);
	ERR_FAIL_COND_V(pattern_set.is_empty(), TileSet::TerrainsPattern());
	for (TileSet::TerrainsPattern &terrain_pattern : pattern_set) {
		int score = 0;
		
		TerrainConstraint terrain_constraint = TerrainConstraint(tile_map_node, p_position, terrain_pattern.get_terrain());
		const RBSet<TerrainConstraint>::Element *in_set_constraint_element = p_constraints.find(terrain_constraint);
		if (in_set_constraint_element) {
			if (in_set_constraint_element->get().get_terrain() != terrain_constraint.get_terrain()) {
				score += in_set_constraint_element->get().get_priority();
			}
		} else if (p_current_pattern.get_terrain() != terrain_pattern.get_terrain()) {
			continue; 
		}
		
		bool invalid_pattern = false;
		for (int i = 0; i < TileSet::CELL_NEIGHBOR_MAX; i++) {
			TileSet::CellNeighbor bit = TileSet::CellNeighbor(i);
			if (tile_set->is_valid_terrain_peering_bit(p_terrain_set, bit)) {