string substitution in command

- [x] I have fzf 0.23.0 or above
- [x] I have read through https://github.com/junegunn/fzf.vim/blob/master/README.md
- [x] I have read through https://github.com/junegunn/fzf/blob/master/README-VIM.md
- [x] I have read through the manual page of fzf (`man fzf`)
- [x] I have searched through the existing issues

I am trying to replicate a shell command in vim and I can't figure out how to get it to work correctly.
In the shell I type
```
notmuch address %s | fzf
```
And I get lovely fzf completion for email addresses.
I am trying to get this to work in vim using
```
:call fzf#run({'source': 'notmuch address %s', 'sink': 'norm i'})
```
Which runs without error, but gives an empty list, I assume that the `%s` part is not translating, but I cannot figure out what I need to change to make it pass that through properly.