chore: add Codecov test analytics

[thomasrockhu-codecov]

Description

Hi, Tom from Codecov here. I saw that you used Codecov already, and I thought you could benefit from catching any flaky or failed tests. We released a Test Analytics product that might be helpful and would love your feedback.

Related Issue

• [ ] Closes #
• [ ] Related to #

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

Type of change

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

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📚 Documentation preview 📚: https://pymc--7768.org.readthedocs.build/en/7768/

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[ricardoV94]

Not sure we need this, even the default codecov job is more annoying these days than not, as it fails to upload most times due to public token limitations

[thomasrockhu-codecov]

@ricardoV94 anything I can do to help with the coverage side of things? What seems to be the problem?