Replace format and % strings with f-strings...* wqflask/wqflask/marker_regression/gemma_mapping.py: Use f-strings
which are easier to read.
(generate_random_n_string): New function.
Update sql query in test...* wqflask/tests/unit/wqflask/api/test_gen_menu.py
(test_build_datasets_with_type_mrna): Update sql query to fix failing
test