### Godot version

v4.0.3.stable.mono.official [5222a99f5]

### System information

macOS Monterey 12.6.6 (21G646)

### Issue description

When creating a tileset by code with custom data layers, removing a layer with `remove_custom_data_layer` does not update the name-to-layer mapping; `get_custom_data_layer_by_name` will continue to return that layer's original index.

This has a downstream effect of causing TileData objects attempting to use `get_custom_data('Layer B')` to return invalid data (whatever custom data is now in Layer B's old index; e.g. Layer C).

I would expect that after using `remove_custom_data_layer`, I would be able to still use `get_custom_data_layer_by_name` on that tileset.

### Steps to reproduce

Run this code to see that getting Layer B by name after removing the first layer continues to return its original index (1) when in reality it is now at index 0.
```
	var tileset:TileSet = TileSet.new()

	tileset.add_custom_data_layer()
	tileset.set_custom_data_layer_name(0, 'Layer A')
	tileset.set_custom_data_layer_type(0, TYPE_INT)

	tileset.add_custom_data_layer()
	tileset.set_custom_data_layer_name(1, 'Layer B')
	tileset.set_custom_data_layer_type(1, TYPE_STRING)

	print('Layer index 0 name : ', tileset.get_custom_data_layer_name(0)) # Layer A
	print('Layer index 1 name : ', tileset.get_custom_data_layer_name(1)) # Layer B
	print('Layer B is on index : ', tileset.get_custom_data_layer_by_name("Layer B")) # 1

	print('----- removing custom data layer 0 -----')
	tileset.remove_custom_data_layer(0)

	print('Layer index 0 name : ', tileset.get_custom_data_layer_name(0)) # Layer B
	print('Layer index 1 name : ', tileset.get_custom_data_layer_name(1)) # prints an error, as expected
	print('Layer B is on index : ', tileset.get_custom_data_layer_by_name("Layer B")) # returns 1 still! should return 0.
```

### Minimal reproduction project

[RemoveCustomDataLayer.zip](https://github.com/godotengine/godot/files/11804762/RemoveCustomDataLayer.zip)

while (sources.has(next_source_id)) {
		next_source_id = (next_source_id + 1) % 1073741824; 
	};
}
int TileSet::add_source(Ref<TileSetSource> p_tile_set_source, int p_atlas_source_id_override) {
	ERR_FAIL_COND_V(!p_tile_set_source.is_valid(), TileSet::INVALID_SOURCE);
	ERR_FAIL_COND_V_MSG(p_atlas_source_id_override >= 0 && (sources.has(p_atlas_source_id_override)), TileSet::INVALID_SOURCE, vformat("Cannot create TileSet atlas source. Another atlas source exists with id %d.", p_atlas_source_id_override));
	ERR_FAIL_COND_V_MSG(p_atlas_source_id_override < 0 && p_atlas_source_id_override != TileSet::INVALID_SOURCE, TileSet::INVALID_SOURCE, vformat("Provided source ID %d is not valid. Negative source IDs are not allowed.", p_atlas_source_id_override));
	int new_source_id = p_atlas_source_id_override >= 0 ? p_atlas_source_id_override : next_source_id;
	sources[new_source_id] = p_tile_set_source;
	source_ids.push_back(new_source_id);
	source_ids.sort();
	TileSet *old_tileset = p_tile_set_source->get_tile_set();
	if (old_tileset != this && old_tileset != nullptr) {
		
		old_tileset->remove_source_ptr(p_tile_set_source.ptr());
	}
	p_tile_set_source->set_tile_set(this);
	_compute_next_source_id();
	sources[new_source_id]->connect(CoreStringNames::get_singleton()->changed, callable_mp(this, &TileSet::_source_changed));
	terrains_cache_dirty = true;
	emit_changed();
	return new_source_id;
}
void TileSet::remove_source(int p_source_id) {