drivers: wifi: esp: fix AT+CWMODE_CUR compatibility with ESP AT 1.7
drivers: wifi: esp: fix AT+CWMODE_CUR compatibility with ESP AT 1.7

There was a regression when implementing automatic AT+CWMODE{,_CUR}
handling based on driver needs. ESP AT 1.7 firmware does not support
AT+CWMODE_CUR=0, which means that radio needs to be either in STA, AP or
STA+AP mode (no NONE state available).

Fix ESP AT 1.7 compatibility by keeping radio in STA mode whenever it is
not used.

Move also first AT+CWMODE_CUR invocation before AT+CWDHCP_CUR, so that
the latter executes successfully with ESP AT 1.7.

Fixes: 03ce61004b35 ("drivers: wifi: esp: control CWMODE depending on
  current needs")
Signed-off-by: Marcin Niestroj <63506c06cfbc47ace147db1702f6e751f5ac2132@grinn-global.com>

galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,Vudentz/zephyr,nashif/zephyr,nashif/zephyr,Vudentz/zephyr,nashif/zephyr,Vudentz/zephyr,zephyrproject-rtos/zephyr,Vudentz/zephyr,nashif/zephyr,zephyrproject-rtos/zephyr,nashif/zephyr,galak/zephyr,finikorg/zephyr,zephyrproject-rtos/zephyr,galak/zephyr,galak/zephyr,zephyrproject-rtos/zephyr,finikorg/zephyr,galak/zephyr,Vudentz/zephyr,Vudentz/zephyr,finikorg/zephyr