Reorder signalModifiedKey in xaddCommand. (#12895)

This PR is a supplement to #11144, moving `signalModifiedKey` in
`xaddCommand` after the trimming, to ensure the state of key eventual
consistency. Currently there is no problem with Redis, but it is better
to avoid issues in future development on Redis.

src/t_stream.c

@@ -2052,7 +2052,6 @@ void xaddCommand(client *c) {
     sds replyid = createStreamIDString(&id);
     addReplyBulkCBuffer(c, replyid, sdslen(replyid));
 
-    signalModifiedKey(c,c->db,c->argv[1]);
     notifyKeyspaceEvent(NOTIFY_STREAM,"xadd",c->argv[1],c->db->id);
     server.dirty++;
 
@@ -2072,6 +2071,8 @@ void xaddCommand(client *c) {
         }
     }
 
+    signalModifiedKey(c,c->db,c->argv[1]);
+
     /* Let's rewrite the ID argument with the one actually generated for
      * AOF/replication propagation. */
     if (!parsed_args.id_given || !parsed_args.seq_given) {