I’m sorry but for now the only solution is to directly Contact the Support usually by the “Ticket System” and ask that they set a 41-bytes Hash password for your Database…
In fact you are Unable to perform this by the Cpanel:
"Please also note that you are now not able to update these passwords in cPanel any longer, as it will revert them back to a 16 byte hash, because MySQL’s password function is set to old_password format. So if you change any of these passwords in cPanel after we’ve converted them to 41-byte hashes, they will become 16-byte again and will need to be re-converted by us."