pyenv: only run if pyenv not in $PATH (#8462)
pyenv: only run if pyenv not in $PATH (#8462)

This is needed if in between the update of `$PATH` the `$commands` parameter hasn't
been updated, i.e. if there was no `rehash` or `hash -rf` or automatic rehash.

Co-authored-by: Marc Cornellà <59979d0011543a9dd9557aea70a057e57c9d0d9e@live.com>
tekniklr/oh-my-zsh,tekniklr/oh-my-zsh