OK -- the non-providers/non-core (a.k.a. "other") group of string normalization has just been merged. So, if you already rebased, unlucky you -- you need to do it again.
But fear not, you won't need to do it yet another time until closer to the release of airflow 2.5, when we'll apply string normalization on the rest of the repo, and this chapter will be closed. Thanks for your patience.