Add CLV plot_expected_purchases_ppc

[ColtAllen]

Description

This PR adds a plotting function for prior and posterior predictive checks of customer purchases.

plot_expected_purchases_ppc(model, ppc='prior');

plot_expected_purchases_ppc(model, ppc='posterior');

I've created an issue for adding HDI ranges to these plots, and while revising the ParetoNBD notebook also removed a model file that was being created.

Related Issue

• Closes Implement validation PPC plots for CLV models #278
• Related to sample_prior_predictive for CLV models #1155, Adapt Evaluation Plots from lifetimes #326, Add HDI ranges to CLV plot_expected_purchases_ppc #1223

Checklist

• Checked that the pre-commit linting/style checks pass
• Included tests that prove the fix is effective or that the new feature works
• Added necessary documentation (docstrings and/or example notebooks)
• If you are a pro: each commit corresponds to a relevant logical change

Modules affected

• MMM
• CLV

Type of change

• New feature / enhancement
• Bug fix
• Documentation
• Maintenance
• Other (please specify):

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📚 Documentation preview 📚: https://pymc-marketing--1222.org.readthedocs.build/en/1222/

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Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 95.64%. Comparing base (7abb6e7) to head (6b559f1).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1222      +/-   ##
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+ Coverage   95.59%   95.64%   +0.04%     
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  Files          39       39              
  Lines        4066     4089      +23     
==========================================
+ Hits         3887     3911      +24     
+ Misses        179      178       -1     

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[ColtAllen]

Three extraneous tests for the MMM and Prior modules are failing in the CI.

[juanitorduz]

Great! 🚀

[juanitorduz]

@ColtAllen we have a fix for the mmm tests failing in #1240. You need to rebase and then we can merge (there are some lint fixes as well)

[juanitorduz]

pre-commit.ci autofix