Fix new evaluation notebook

[juanitorduz]

Closes #1372

• Harmonize colors
• Fix titles being shifted in the prior - posterior plots
• Watermark
• Harmonize numpy type hints.

FYI @louismagowan :)

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📚 Documentation preview 📚: https://pymc-marketing--1374.org.readthedocs.build/en/1374/

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Codecov Report

Attention: Patch coverage is 16.66667% with 5 lines in your changes missing coverage. Please review.

Project coverage is 93.92%. Comparing base (7986a9c) to head (7deef59).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
pymc_marketing/mmm/mmm.py	0.00%	5 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1374      +/-   ##
==========================================
+ Coverage   93.86%   93.92%   +0.05%     
==========================================
  Files          48       48              
  Lines        5135     5133       -2     
==========================================
+ Hits         4820     4821       +1     
+ Misses        315      312       -3     

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[wd60622]

Thanks @juanitorduz

[louismagowan]

Thanks @juanitorduz! 😁