HttpShardHandler: Fix extension hook (apache#2661)

HttpShardHandler.transformResponse is an extension hook for subclasses to transform the shard response. Ever since 9.0 when the HTTP2 Async stuff landed, this hook became inoperable/dormant (method existed but hasn't been called anymore). This brings it back.

Co-authored-by: Gilles Bellaton <[email protected]>

solr/core/src/java/org/apache/solr/handler/component/HttpShardHandler.java

@@ -168,15 +168,15 @@ public void submit(
             srsp.setShardAddress(rsp.getServer());
             ssr.elapsedTime =
                 TimeUnit.MILLISECONDS.convert(System.nanoTime() - startTime, TimeUnit.NANOSECONDS);
-            responses.add(srsp);
+            responses.add(transfomResponse(sreq, srsp, shard));
           } else if (throwable != null) {
             ssr.elapsedTime =
                 TimeUnit.MILLISECONDS.convert(System.nanoTime() - startTime, TimeUnit.NANOSECONDS);
             srsp.setException(throwable);
             if (throwable instanceof SolrException) {
               srsp.setResponseCode(((SolrException) throwable).code());
             }
-            responses.add(srsp);
+            responses.add(transfomResponse(sreq, srsp, shard));
           }
         });