[nitpick] pubchem_id / cell_line_name hard coded in visualization/utils

Instead, we should use CELL_LINE_IDENTIFIER, DRUG_IDENTIFIER https://github.com/daisybio/drevalpy/blob/0cadbb6aef5b26aca254c05ab51ed782d9cee6e9/drevalpy/visualization/utils.py#L254-L274