drivers: wifi: esp32: create event handling thread in runtime
drivers: wifi: esp32: create event handling thread in runtime

Commit 95b916d1045e ("drivers: wifi: esp32: fix reconnect issue")
switched from thread created at runtime to statically defined thread.
The difference is mainly visible for simple applications that use
CONFIG_NET_CONFIG_AUTO_INIT=y, where networking setup code is executed
before main() and any statically defined threads. All ESP32 events are
just queued and never handled, so conditions enforced by
CONFIG_NET_CONFIG_NEED_IPV4=y are never met (e.g. Zephyr networking
layer is never informed about being connected).

Switch back to thread created at runtime, which starts at the moment
when k_thread_create() is invoked. This allows ESP32 event processing to
happen just after ESP32 WiFi driver gets initialized and before Zephyr
network auto initialization code (CONFIG_NET_CONFIG_AUTO_INIT=y).

Signed-off-by: Marcin Niestroj <63506c06cfbc47ace147db1702f6e751f5ac2132@emb.dev>

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