Remove animal sniffer from REST client sniffer

Animal sniffer is no longer needed, we can remove it for sniffer like
we did for the low-level REST client with elastic#29646

Author: javanna

client/sniffer/build.gradle

@@ -20,7 +20,6 @@
 import org.elasticsearch.gradle.precommit.PrecommitTasks
 
 apply plugin: 'elasticsearch.build'
-apply plugin: 'ru.vyarus.animalsniffer'
 apply plugin: 'nebula.maven-base-publish'
 apply plugin: 'nebula.maven-scm'
 
@@ -52,8 +51,6 @@ dependencies {
   testCompile "org.hamcrest:hamcrest-all:${versions.hamcrest}"
   testCompile "org.elasticsearch:securemock:${versions.securemock}"
   testCompile "org.elasticsearch:mocksocket:${versions.mocksocket}"
-  testCompile "org.codehaus.mojo:animal-sniffer-annotations:1.15"
-  signature "org.codehaus.mojo.signature:java17:1.0@signature"
 }
 
 forbiddenApisMain {

client/sniffer/src/test/java/org/elasticsearch/client/sniff/ElasticsearchHostsSnifferTests.java

@@ -60,8 +60,6 @@
 import static org.junit.Assert.assertThat;
 import static org.junit.Assert.fail;
 
-//animal-sniffer doesn't like our usage of com.sun.net.httpserver.* classes
-@IgnoreJRERequirement
 public class ElasticsearchHostsSnifferTests extends RestClientTestCase {
 
     private int sniffRequestTimeout;