drivers: flash_shell: Fix write protection in the test command
drivers: flash_shell: Fix write protection in the test command

Flash drivers are free to re-enable write protection after a write or
erase operation is complete. Therefore write protection has to be
disabled before any such operation.

Signed-off-by: Ievgenii Meshcheriakov <df2064527cff29064d40b3c65720cad00a28b85e@nordicsemi.no>

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