Fix warn that fails compile

We don't throw any exception in `close` so we shouldn't declare
that we do. Declaring that we do angers that java gods because
we might throw `InterruptedException` which is evil to throw
in `close`.

Original commit: elastic/x-pack-elasticsearch@49ca8143d7

sql-clients/test-utils/src/main/java/org/elasticsearch/xpack/sql/test/server/ProtoHandler.java

@@ -83,7 +83,7 @@ public abstract class ProtoHandler<R> implements HttpHandler, AutoCloseable {
     }
 
     @Override
-    public void close() throws Exception {
+    public void close() {
         // no-op
     }
 }