evil-collection-magit-section introduces some redundant keybinds on
number keys 1-4, so our hack to correct these keys needed an adjustment.
And by unbinding these keys at the source (magit-section-mode-map), we
don't have to do the same for each inheriting keymap (like
code-review-mode-map and magit-mode-map).
Ref: emacs-evil/evil-collection@e26c869735
Amend: 31519d393a