Tqz/utils refactor

[ztq1996]

Problem & Solution Description (including issue #)

Code Quality

• My code follows the code style of this project
• I have written unit tests or justified all instances of #pragma: no cover; in the case of a bugfix, a new test that breaks as a result of the bug has been added
• My code contains relevant comments and necessary documentation for future maintainers; the change is reflected in applicable demos/tutorials (with output cleared!) and added/updated docstrings use the NumPy docstring format
• Any breaking changes, described above, are accompanied by backwards compatibility and deprecation warnings

[ztq1996]

@sschmidt23 Seems like one unit test failed genuinely here, has that always been the case?

[sschmidt23]

Hmm, I have seen this test fail every once in a while, our test set galaxies are all very low redshift with fairly flat PDFs, so the mode can sometimes shift a bit when even small changes are introduced (maybe by things like updates to numpy/scipy). I think several of the other estimators have commented out the np.isclose assert statement because of similar issues. I'll look into it shortly.

[sschmidt23]

I updated to new values and added an atol=0.03. If there are more failures in the future we can think about just dropping the assert statement that checks expected values.

[ztq1996]

Thank you Sam!