[Bugfix] Temporarily modify single table demo data link

[MooooCat]

Description

Due to datahub.io issues, all current pytest unit tests fail because they cannot download the demo data.

Currently, we modify the link to the data set to temporarily solve this problem.

Motivation and Context

How has this been tested?

Types of changes

• Maintenance (no change in code, maintain the project's CI, docs, etc.)
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[codecov-commenter]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (dd70515) 78.58% compared to head (8d88aa5) 78.94%.
Report is 1 commits behind head on main.

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Additional details and impacted files

@@            Coverage Diff             @@
##             main     #121      +/-   ##
==========================================
+ Coverage   78.58%   78.94%   +0.36%     
==========================================
  Files          64       64              
  Lines        2764     2764              
==========================================
+ Hits         2172     2182      +10     
+ Misses        592      582      -10     

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