Fix code for reading uberon site mapping csv file

[msierk]

Need to fix code in op_uberon_mapper for reading in oncopacket/src/oncopacket/ncit_mapping_files/CDA_primary_diagnosis_site_to_uberon.csv.

[justaddcoffee]

Link to failing CI

[justaddcoffee]

One solution might be something like this:

import importlib.resources

# Assuming the mapping file is inside the 'ncit_mapping_files' package (which is a subpackage of your module)
with importlib.resources.open_text('oncopacket.ncit_mapping_files', 'CDA_primary_diagnosis_site_to_uberon.csv') as f:
    site_to_uberon = pd.read_csv(f)

(Also probably best practice is to make PRs before merging into develop, and fix the CI failure in the branch for the PR)