improve CellLine metadata module UX

[JiriBruthans]

PR Checklist

• Referenced issue is linked
• Documentation in docs is updated

Description of changes

Updated documentation for CellLine.annotate_bulk_rna and CellLine.annotate.
Improved handeling of default parameters for CellLine.annotate_bulk_rna.
Replaced warning with error in CellLine.correlate if genes don't match.
Updated CellLine.annotate_protein_expression for example in documentation to work.

Additional context

Fixes #664

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 33.33333% with 8 lines in your changes missing coverage. Please review.

Project coverage is 65.77%. Comparing base (7b9d965) to head (18da81d).

Files with missing lines	Patch %	Lines
pertpy/metadata/_cell_line.py	33.33%	8 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #717      +/-   ##
==========================================
- Coverage   65.79%   65.77%   -0.03%     
==========================================
  Files          47       47              
  Lines        6137     6144       +7     
==========================================
+ Hits         4038     4041       +3     
- Misses       2099     2103       +4     

Files with missing lines	Coverage Δ
pertpy/metadata/_cell_line.py	52.75% <33.33%> (-0.60%)	⬇️

... and 1 file with indirect coverage changes

[Zethson]

Thank you very much!

Please ensure that your tutorials submodule is up to date. There should not be any changes to it in this PR.

This generally looks good!

[Zethson]

Great, thank you very much!