docs: wifi: wifi_guide update for disconnection warning in case of invalid initiation in `WIFI_MODE_APSTA`.
docs: wifi: wifi_guide update for disconnection warning in case of invalid initiation in `WIFI_MODE_APSTA`.

    Added warning to expect momentary disconnection of exSTA if channel of exAP is different than that of softAP and a prescribed solution.

espressif/esp-idf,espressif/esp-idf,espressif/esp-idf,espressif/esp-idf