Anjay-zephyr 3.8.1

Improvements

• Fixed compatibility with the newest versions of Zephyr (3.6.0) and nRF Connect SDK (2.7.0)
• Added support for polling multiple sockets using es-WiFi module
• Imply STREAM_FLASH_ERASE and IMG_ERASE_PROGRESSIVELY when using
  ANJAY_ZEPHYR_FOTA, warn user if IMG_ERASE_PROGRESSIVELY is disabled.

Bugfixes

• Fixed faulty assertion in src/objects/ecid.c
• Fixed Modem FOTA status reporting mechanism on nRF9160 with NCS v2.5.0 and up
• Clear the flash area manually for FOTA image if IMG_ERASE_PROGRESSIVELY is not
  enabled.