Revert "mypy: 0.761 -> 0.770"
Revert "mypy: 0.761 -> 0.770"

This reverts commit e7c3e277b621e281c44d5835a97215ec2d2f8739.

See https://github.com/NixOS/nixpkgs/issues/83458

This currently blocks the channel.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs