Remove unnecessary replication backlog memory copy (#9157)

in the past, the reply list was a list of sds objects, so this didn't have any overhead,
but now addReplySds just copies the data from the sds and frees it, so there's no
need to make a copy of the buffer before copying again.
this reduces an excessive allocation and free and a memcpy.

src/replication.c

@@ -463,7 +463,7 @@ long long addReplyReplicationBacklog(client *c, long long offset) {
             (server.repl_backlog_size - j) : len;
 
         serverLog(LL_DEBUG, "[PSYNC] addReply() length: %lld", thislen);
-        addReplySds(c,sdsnewlen(server.repl_backlog + j, thislen));
+        addReplyProto(c,server.repl_backlog + j, thislen);
         len -= thislen;
         j = 0;
     }