WebUI: reword OTP info message displayed during PW reset
    
    The message displayed before is now limited to the OTP
    sync form, for which it was written originally.
    A new message is introduced for the PW reset form,
    which clarifies the usage of the OTP field.
    
    Fixes: https://pagure.io/freeipa/issue/5628
    Reviewed-By: Alexander Bokovoy <abbra@users.noreply.github.com>