[QML RENAMING] Update demo

[doctorperceptron]

The tutorial_qft_arithmetics demo has a hard-coded URL to an image hosted in the qml repo. We have renamed this repo, so this PR updates the image URL to point our cloud assets location instead.

Also replaced a link to the old codebook.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 97.12%. Comparing base (23d05f5) to head (369ebf1).
⚠️ Report is 2 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2494   +/-   ##
=======================================
  Coverage   97.12%   97.12%           
=======================================
  Files         156      156           
  Lines       17733    17733           
  Branches     1696     1696           
=======================================
  Hits        17223    17223           
  Misses        373      373           
  Partials      137      137           

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[github-actions]

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