### 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)

if (has_source(a[0]) && get_source(a[0])->has_tile(a[1]) && get_source(a[0])->has_alternative_tile(a[1], a[2])) {
			alternative_to_remove.push_back(a);
		}
	}
	for (int i = 0; i < alternative_to_remove.size(); i++) {
		Array a = alternative_to_remove[i];
		remove_alternative_level_tile_proxy(a[0], a[1], a[2]);
	}
}
void TileSet::clear_tile_proxies() {
	source_level_proxies.clear();
	coords_level_proxies.clear();
	alternative_level_proxies.clear();
	emit_changed();
}
int TileSet::add_pattern(Ref<TileMapPattern> p_pattern, int p_index) {
	ERR_FAIL_COND_V(!p_pattern.is_valid(), -1);
	ERR_FAIL_COND_V_MSG(p_pattern->is_empty(), -1, "Cannot add an empty pattern to the TileSet.");
	for (const Ref<TileMapPattern> &pattern : patterns) {
		ERR_FAIL_COND_V_MSG(pattern == p_pattern, -1, "TileSet has already this pattern.");
	}
	ERR_FAIL_COND_V(p_index > (int)patterns.size(), -1);
	if (p_index < 0) {
		p_index = patterns.size();
	}
	patterns.insert(p_index, p_pattern);
	emit_changed();
	return p_index;
}
Ref<TileMapPattern> TileSet::get_pattern(int p_index) {