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
String entity = EntityUtils.toString(response.getEntity());
        logger.info("Response entity as string: " + entity);
        return (JSONObject) parser.parse(entity);
    }
    private void configureJsonRequest(HttpEntityEnclosingRequestBase request, String jsonBody) {
        StringEntity entity = new StringEntity(jsonBody, ContentType.APPLICATION_JSON);
        request.setEntity(entity);
        request.setHeader("Accept", "application/json");
        request.setHeader("Content-type", "application/json");
    }
    private void assertHttpOk(StatusLine status) {
        assertThat("Unexpected HTTP Response status: " + status, status.getStatusCode(), Matchers.equalTo(200));
    }
    protected RestClient getElasticsearchClient() throws IOException {
        return buildClient(restAdminSettings(), new HttpHost[] { new HttpHost("localhost", Integer.parseInt(ES_PORT), "https") });
    }
    protected Map<String, Object> callAuthenticateApiUsingBearerToken(String accessToken) throws Exception {
        return callAuthenticateApiUsingBearerToken(accessToken, RequestOptions.DEFAULT);
    }
    protected Map<String, Object> callAuthenticateApiUsingBearerToken(String accessToken, RequestOptions baseOptions) throws IOException {
        Request request = new Request("GET", "/_security/_authenticate");
        RequestOptions.Builder options = baseOptions.toBuilder();
        options.addHeader("Authorization", "Bearer " + accessToken);
        request.setOptions(options);
        try (RestClient restClient = getElasticsearchClient()) {
            return entityAsMap(restClient.performRequest(request));
        }
    }
}