Hande CI differences in AnnData snapshots

Adding the snapshots as done in #339 seems to not be fully sufficient.
https://github.com/AlexsLemonade/scpcaTools/actions/runs/24194740458

Something about the file format is a bit different with the latest versions `zellkonverter`, most likely, because we are now getting errors that the files are different. However, all the other checks for the internal content are correct. If we think those are sufficient, we can probably suppress the snapshot check in CI as described at https://testthat.r-lib.org/reference/expect_snapshot_file.html

This is not a priority for now, but certainly something we should revisit.

Start with the CI run linked in the issue and compare the snapshot work from #339 with the current AnnData files produced by the latest zellkonverter versions. Read testthat’s expect_snapshot_file documentation to evaluate whether the difference is only file formatting. Done means deciding between updating the snapshots and suppressing that check while retaining the existing internal-content checks.

Written by the indexing model from the issue text.