Add proper test Custom values (#1147)

* add proper tests for custom values

* remove try operators

* use sustrate compat for import of hash

* add license and hex

* add script to artifacts.sh

* custom values with ids not in metadata can be accessed in static interface

* fmt and clippy

* access bytes of custom values directly, even if type id wrong

* final fixes

* removing substrate-compat flag from ui tests

* Update subxt/src/custom_values/custom_values_client.rs

Co-authored-by: James Wilson <james@jsdw.me>

* remove types access in type generator

* 2 extra lines

---------

Co-authored-by: James Wilson <james@jsdw.me>

testing/generate-custom-metadata/src/main.rs

@@ -0,0 +1,17 @@
+// Copyright 2019-2023 Parity Technologies (UK) Ltd.
+// This file is dual-licensed as Apache-2.0 or GPL-3.0.
+// see LICENSE for license details.
+
+use codec::Encode;
+use std::io::{self, Write};
+
+/// Creates some scale encoded metadata with custom values and writes it out to stdout (as raw bytes)
+///
+/// Can be called from the root of the project with: `cargo run --bin generate-custom-metadata > output.scale`.
+fn main() -> io::Result<()> {
+    let metadata_prefixed = generate_custom_metadata::metadata_custom_values_foo();
+    let stdout = io::stdout();
+    let mut handle = stdout.lock();
+    handle.write_all(&metadata_prefixed.encode())?;
+    Ok(())
+}