samples: wifi: esp32s2_saola: reduce RAM usage

This modification frees up around ~10kB of RAM and make sample code
working again.

1) Reduced net packet size and count.
2) Increase Wi-Fi heap to avoid memory allocation failure.
3) Keep log as minimal.

Signed-off-by: Sylvio Alves <sylvio.alves@espressif.com>