test(channel): attempt to reduce test flakiness

https://github.com/emqx/emqx/actions/runs/5124277038/jobs/9217362541?pr=10886#step:5:1582
```
%%% emqx_channel_SUITE ==> t_handle_kicked_publish_will_msg: FAILED
%%% emqx_channel_SUITE ==> will_message_not_published
```

apps/emqx/test/emqx_channel_SUITE.erl

@@ -892,7 +892,7 @@ t_handle_kicked_publish_will_msg(_) ->
     ),
     receive
         {pub, Msg} -> ok
-    after 1_000 -> exit(will_message_not_published)
+    after 10_000 -> exit(will_message_not_published)
     end.
 
 t_handle_call_discard(_) ->