This function reads a CSV file provided by the user and extracts
search criteria based on a specified search type (either "barcode" or "study_subject").
Usage
extract_search_criteria(user_csv, search_type)
Arguments
user_csv
A path to the user-provided CSV file.
search_type
A string indicating the type of search ("barcode" or "study_subject").
Value
A message indicating whether the required columns were detected.
