It seems the `c2id/c2id-server` docker image has dissappeared from DockerHub so our idp-fixture that depends on it can no longer start. This is currently only required by our `oidc-op-tests` project so for now I've disabled these tests. We'll need to find an alternative fixture here. I tried simply replacing it with the `c2id-server-demo` image but it wasn't a direct replacement.

https://gradle-enterprise.elastic.co/s/p4vwhzkudvutw
x-pack/qa/oidc-op-tests/src/javaRestTest/java/org/elasticsearch/xpack/security/authc/oidc/C2IdOpTestCase.java
protected static final String C2ID_AUTH_ENDPOINT = "http://127.0.0.1:" + C2OP_PORT + "/c2id-login";
    private static final String ES_PORT = getEphemeralTcpPortFromProperty("elasticsearch-node", "9200");
    
    private static final String OP_API_BEARER_TOKEN = "811fa888f3e0fdc9e01d4201bfeee46a";
    private static Path HTTP_TRUSTED_CERT;
    @BeforeClass
    public static void readTrustedCert() throws Exception {
        final URL resource = OpenIdConnectAuthIT.class.getResource("/testnode_ec.crt");
        if (resource == null) {
            throw new FileNotFoundException("Cannot find classpath resource /testnode_ec.crt");
        }
        HTTP_TRUSTED_CERT = PathUtils.get(resource.toURI());
    }
    protected static String getEphemeralTcpPortFromProperty(String service, String port) {
        String key = "test.fixtures." + service + ".tcp." + port;
        final String value = System.getProperty(key);
        assertNotNull("Expected the actual value for port " + port + " to be in system property " + key, value);
        return value;
    }
    /**
     * Register one or more OIDC clients on the C2id server. This should be done once (per client) only.
     * C2id server only supports dynamic registration, so we can't pre-seed its config with our client data.
     */
    protected static void registerClients(String... jsonBody) throws IOException {
        try (CloseableHttpClient httpClient = HttpClients.createDefault()) {
            final BasicHttpContext context = new BasicHttpContext();
            final List<HttpPost> requests = new ArrayList<>(jsonBody.length);
            for (String body : jsonBody) {
                HttpPost httpPost = new HttpPost(C2ID_REGISTRATION_URL);
                httpPost.setEntity(new StringEntity(body, ContentType.APPLICATION_JSON));