Fix redis-cli pubsub_mode and connect minor prompt / crash issue (#12571)

When entering pubsub mode and using the redis-cli only
connect command, we need to reset pubsub_mode because
we switch to a different connection.

This will affect the prompt when the connection is successful,
and redis-cli will crash when the connect fails:
```
127.0.0.1:6379> subscribe ch
1) "subscribe"
2) "ch"
3) (integer) 1
127.0.0.1:6379(subscribed mode)> connect 127.0.0.1 6380
127.0.0.1:6380(subscribed mode)> ping
PONG
127.0.0.1:6380(subscribed mode)> connect a b
Could not connect to Redis at a:0: Name or service not known
Segmentation fault
```

(cherry picked from commit 4de4fcf280648519239927d408624ea34953c0e0)

src/redis-cli.c

@@ -1657,6 +1657,7 @@ static int cliConnect(int flags) {
             redisFree(context);
             config.dbnum = 0;
             config.in_multi = 0;
+            config.pubsub_mode = 0;
             cliRefreshPrompt();
         }