Fix unstable CI

[djhoese]

Remove unnecessary zarr dependency causing complications in unstable CI (it's annoying to install all of its dependencies manually).

• [ ] Closes #xxxx
• [ ] Tests added
• [ ] Tests passed
• [ ] Passes git diff origin/main **/*py | flake8 --diff
• [ ] Fully documented

[codecov[bot]]

Codecov Report

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

Project coverage is 93.97%. Comparing base (56f4506) to head (dd89e71). Report is 5 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #605 +/- ## ========================================== - Coverage 94.01% 93.97% -0.04% ========================================== Files 92 86 -6 Lines 13836 13746 -90 ========================================== - Hits 13008 12918 -90 Misses 828 828 ``` | [Flag](https://app.codecov.io/gh/pytroll/pyresample/pull/605/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pytroll) | Coverage Δ | | |---|---|---| | [unittests](https://app.codecov.io/gh/pytroll/pyresample/pull/605/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=pytroll) | `93.97% <ø> (-0.04%)` | :arrow_down: | 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=pytroll#carryforward-flags-in-the-pull-request-comment) to find out more.

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[coveralls]

coverage: 93.676%. remained the same when pulling dd89e7131247ed99d99534fa08d331d8ad88584d on djhoese:ci-fix-unstable into db94a87b21bfff43eecb71458f54c574dd344833 on pytroll:main.