[python] Fix wrong parameters in ExperimentDataPipe

[ebezzi]

Not sure how those ended up there in the first place.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 91.12%. Comparing base (96c0499) to head (d15c98b).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #1178 +/- ## ======================================= Coverage 91.12% 91.12% ======================================= Files 77 77 Lines 5902 5902 ======================================= Hits 5378 5378 Misses 524 524 ``` | [Flag](https://app.codecov.io/gh/chanzuckerberg/cellxgene-census/pull/1178/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/chanzuckerberg/cellxgene-census/pull/1178/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg) | `91.12% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=chanzuckerberg#carryforward-flags-in-the-pull-request-comment) to find out more.

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[atolopko-czi]

Not sure how those ended up there in the first place.

It was lacking a proper test! 😳 Probably should add one to test the defaults since all of the existing tests explicitly set these two params.