Ensure that additional adata columns are not removed in the denoise step

[ptajvar]

Information added to adata are removed in the denoise step. This happens because marker adata is recalculated since denoising changes marker counts for each component and some of the statistics should be recalculated. The fix is to add back any columns that are missing in the new adata from the old adata.

Fixes: #PNA-2075

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

We now add a dummy column before denoising and check if it still exists after denoising.

PR checklist:

• This comment contains a description of changes (with reason).
• I have performed a self-review of my own code
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• If a new tool or package is included, I have updated dependencies in pyproject.toml and cited it properly
• I have checked my code and documentation and corrected any misspellings
• I have documented any significant changes to the code in CHANGELOG.md

[johandahlberg]

See my inline comment. Lets fix that and then merge this.