Remove joint_logprob function from tests.logprob.utils

[shreyas3156]

What is this PR about?
Closes #6619

The joint_logprob() function in tests.logprob.utils uses factorized_joint_logprob() and only checks for summing over the dimensions of the logp calculated. It can therefore be replaced with logp() or factorized_joint_logprob() depending on the number of RVs to be calculated, with an additional statement to sum over the dimensions in the test cases.

Checklist

• Explain important implementation details 👆
• Make sure that the pre-commit linting/style checks pass.
• Link relevant issues (preferably in nice commit messages)
• Are the changes covered by tests and docstrings?
• Fill out the short summary sections 👇

Major / Breaking Changes

• None

Maintenance

• Removing the method should somewhat decrease the functional overhead.

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📚 Documentation preview 📚: https://pymc--6650.org.readthedocs.build/en/6650/

[ricardoV94]

Looks good, just spotted some test name changes and one test that should be moved or removed.

[codecov]

Codecov Report

Merging #6650 (6ef753b) into main (1ed4475) will not change coverage.
The diff coverage is n/a.

❗ Current head 6ef753b differs from pull request most recent head 1b8bbfd. Consider uploading reports for the commit 1b8bbfd to get more accurate results

Additional details and impacted files

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  Coverage   91.99%   91.99%           
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  Files          94       94           
  Lines       15944    15944           
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  Hits        14667    14667           
  Misses       1277     1277           

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