drivers: wifi: esp: don't queue send after socket connect

After a synchronous (timeout > 0) connection attempt was made, it was
being checked if there is some packet to be sent. If positive, then a
send work was queued.

This behavior makes little sense, as TCP connection is not even
considered established at this point (from net_context perspective) if
function has not returned yet. Additionally it differs from
asynchronous (timeout == 0) connection attempt. In case of UDP (and
calling esp_connect() from esp_sendto()) sock->tx_pkt is assured to be
NULL. Drop this piece of code as it doesn't seem to be justified.

Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>