replace prepare_for_sbi in tutorials

[zinaStef]

It replaces in the relevant tutorial notebooks the simulator, prior = prepare_for_sbi(custom_simulator, custom_prior) by

prior, num_parameters, prior_returns_numpy = process_prior(custom_prior)

simulator = process_simulator(simulator, prior, prior_returns_numpy)

Fixes #752

Checklist:

• I have read and understood the contribution
  guidelines
• I agree with re-licensing my contribution from AGPLv3 to Apache-2.0.
• I have commented my code, particularly in hard-to-understand areas
• I have added tests that prove my fix is effective or that my feature works
• I have reported how long the new tests run and potentially marked them
  with pytest.mark.slow.
• New and existing unit tests pass locally with my changes
• I performed linting and formatting as described in the contribution
  guidelines
• I rebased on main (or there are no conflicts with main)

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 76.37%. Comparing base (7c81e9e) to head (1e51770).
Report is 2 commits behind head on main.

❗ Current head 1e51770 differs from pull request most recent head d20b129. Consider uploading reports for the commit d20b129 to get more accurate results

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1013   +/-   ##
=======================================
  Coverage   76.37%   76.37%           
=======================================
  Files          84       84           
  Lines        6507     6507           
=======================================
  Hits         4970     4970           
  Misses       1537     1537           

Flag	Coverage Δ
unittests	76.37% <ø> (ø)

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[augustes]

an issue has to be raised for this notebook as it throws an error but not related to replace prepare_for_sbi

[augustes]

A separate issue has to be raised for notebook 14_iid as it throws an error but not related to replace prepare_for_sbi

[janfb]

There is a conflict with main now because of #1003 being merged. Please resolve it locally by

• checkout locally on main and pull the most recent version
• checkout on your feature branch
• rebase on main: git rebase main
• resolve the appearing merge conflicts manually.

Alternatively, as resolving conflicts in notebooks can be painful, you could open a new branch from most recent main and apply your changes from scratch.

Let me know if you have questions.