Is forgetting the mention of the evil eye in the Qur’an, and then remembering a verse about it in Surat Yusuf, considered disbelief?

What you said is not disbelief, for denying something from the Qur'an due to error or delusion is not disbelief. The sin of error has been lifted from this Ummah. Allah Almighty said: "And there is no blame upon you for that in which you have erred, but [only for] what your hearts intended. And ever is Allah Forgiving and Merciful." The verse you are referring to does not explicitly mention the evil eye at all.