Fixed ibd.py CLI so that it works with the latest argument inputs

[gtsambos]

This is a very small change that updates the simple CLI at the bottom of the ibd.py script so that it works again. Since there are now a number of PRs that require me to use this CLI for testing (#2460 , #2462), I thought I'd submit this change separately so that I only have to do it once, and to avoid possible merge conflicts further down the line.

[jeromekelleher]

@Mergifyio rebase

[mergify]

rebase

✅ Branch has been successfully rebased

[codecov]

Codecov Report

Merging #2497 (365092c) into main (96365a9) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##             main    #2497   +/-   ##
=======================================
  Coverage   93.91%   93.91%           
=======================================
  Files          28       28           
  Lines       27213    27213           
  Branches     1260     1261    +1     
=======================================
  Hits        25556    25556           
  Misses       1623     1623           
  Partials       34       34           

Flag	Coverage Δ
c-tests	92.24% <ø> (ø)
lwt-tests	89.05% <ø> (ø)
python-c-tests	71.69% <ø> (ø)
python-tests	98.96% <ø> (ø)

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