Fixed proxy server closing

Author: alex268

tests/common/src/main/java/tech/ydb/test/integration/docker/GrpcProxyServer.java

@@ -62,6 +62,12 @@ public EndpointRecord endpoint() {
     @Override
     public void close() {
         server.shutdown();
+        try {
+            server.awaitTermination(60, TimeUnit.SECONDS);
+        } catch (InterruptedException ex) {
+            logger.error("cannot await proxy server closing", ex);
+            Thread.currentThread().interrupt();
+        }
     }
 
     private static class CallProxy<ReqT, RespT> {

tests/common/src/main/java/tech/ydb/test/integration/docker/ProxedDockerHelperFactory.java

@@ -1,6 +1,7 @@
 package tech.ydb.test.integration.docker;
 
 
+
 import io.grpc.Grpc;
 import io.grpc.InsecureChannelCredentials;
 import io.grpc.ManagedChannel;
@@ -75,6 +76,7 @@ public byte[] pemCert() {
             @Override
             public void close() {
                 server.close();
+                channel.shutdownNow();
 
                 if (env.dockerReuse() && TestcontainersConfiguration.getInstance().environmentSupportsReuse()) {
                     return;