redis-cli: always exit if connection fails.

In standalone mode, when a `-REDIRECT` error occurs, special handling is
required if the client is in the `MULTI` context.

We have adopted the same handling method as the cluster mode:

1. If a command in the transaction encounters a `REDIRECT` at the time
of queuing, the execution of `EXEC` will return an `EXECABORT` error (we
expect the client to redirect and discard the transaction upon receiving
a `REDIRECT`). That is:

    ```
    MULTI    ==>  +OK
    SET x y  ==>  -REDIRECT
    EXEC     ==>  -EXECABORT
    ```
2. If all commands are successfully queued (i.e., `QUEUED` results are
received) but a redirect is detected during `EXEC` execution (such as a
primary-replica switch), a `REDIRECT` is returned to instruct the client
to perform a redirect. That is:

    ```
    MULTI    ==>  +OK
    SET x y  ==>  +QUEUED
    failover
    EXEC     ==>  -REDIRECT
    ```

---------

Signed-off-by: zhaozhao.zz <[email protected]>

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