Is it legislated to say "Seek forgiveness for the deceased" while carrying the bier?

Supplicating for the deceased and seeking forgiveness for them is a prescribed act of worship. However, it is disliked to supplicate loudly and raise one's voice in seeking forgiveness for them during the funeral procession, as this is considered an innovated practice. The early Muslims (Salaf) disliked this and considered it a form of clamor. Ibn 'Umar said to someone who raised his voice in seeking forgiveness: "May Allah not forgive you."