STM32U5: When setting option bytes BL2 might corrupt FLASH_SECWM1R1

Due to this [line of code](https://github.com/TrustedFirmware-M/trusted-firmware-m/blob/bbced4bc7bce72fcf822fb56a8e8db00488ff1c0/platform/ext/target/stm/common/stm32u5xx/bl2/low_level_security.c#L812) BL2 on STM32U5 will corrupt WMSecStartPage, when both Hide Protection (HDP) and Secure Area (WMSEC) have to be reconfigured.