fix(test): fix a timing issue in pubsub test

[cxljs]

Description

Recent github action have encountered sporadic errors, such as case https://github.com/redis/go-redis/actions/runs/17021636203/job/48251478581?pr=3481 (This also occurred in PR #3496 , but I couldn't find the error logs after resubmitting).

The error log:

• [FAILED] [0.005 seconds]
PubSub [It] should sharded pub/sub channels
/home/runner/work/go-redis/go-redis/pubsub_test.go:108

  [FAILED] Expected
      <[]string | len:0, cap:0>: []
  to consist of
      <[]string | len:2, cap:2>: ["mychannel", "mychannel2"]
  the missing elements were
      <[]string | len:2, cap:2>: ["mychannel", "mychannel2"]
  In [It] at: /home/runner/work/go-redis/go-redis/pubsub_test.go:118 @ 08/17/25 13:35:51.76

Reason

The reason is that after sending the ssubscribe command, the pubsub shardchannels command was immediately called without waiting for Redis to process the ssubscribe command, resulting in unexpected results.

Solution

sleep 10ms to wait for Redis to finish processing the command.

[ndyakov]

Hey @cxljs, thank you, I did fix this in a separate branch but let's merge this PR and I wil rebase.

[cxljs]

Hey @cxljs, thank you, I did fix this in a separate branch but let's merge this PR and I wil rebase.

@ndyakov I'm really sorry, I didn't know you had already fixed this issue. I just found it in #3496 and and went ahead to fix it together.

[ndyakov]

No worries at all, thank you once again for fixing it!