On every system boot the encrypted user password is written from the config into theoperating system. This information will leak into the generated bootchart when debugging the system startup time issue.

Only pass the encrypted string to the operating system when the password is really changed.

As the system boot timing option is for deleopers only and rather new this does not pose a security risk, to enable it read https://docs.vyos.io/en/latest/contributing/development.html#boot-timing.