Notebook tests fixes

[MichaelClerx]

• Interfaces notebooks require older python because stan doesn't support 3.13 yet
• Renewal-estimation notebook uses pandas, wasn't easy to replace so added pandas installation to notebook testing

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 100.00%. Comparing base (37c4778) to head (bb5903f).
Report is 3 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff            @@
##              main     #1701   +/-   ##
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  Coverage   100.00%   100.00%           
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  Files           97        97           
  Lines         9699      9699           
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  Hits          9699      9699           

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