Queries the ForceDecks API, joins trials/tests/profiles/result definitions, and writes a CSV file to the user's Downloads/VALD_Exports folder (by default).
export_forcedecks_csv(export_dir = NULL)Invisibly, the full path to the created CSV file.
Optional directory to write the CSV to. If NULL,
uses ~/Downloads/VALD_Exports.
This export is ForceDecks-specific and uses the stored start date from
get_start_date(), which is automatically updated by the ForceDecks
data retrieval functions.