esp32: backport some WiFi fixes to v3.0

Fix following WiFi bugs:
1. Fix some potential memory leak caused by WiFi stop
2. Fix the bug that ESP32 AP crashes when connected STA power-off
3. Fix the bug that STA can scan the channel out of regdomain
4. Fix some scan/connect bugs
5. Fix the bug that ESP32 STA fails to connect WPA_WPA2_PSK Apple AP
6. Fix the crashing in scan done because of uint8 overflow
7. Fix the bug that smartconfig crashes when no AP is found
8. Fix the bug that ESP32 sends broadcast to phone after smartconfig is done