Privileges: GAIA_MODIFY

Replaces federated search dataset selection for the account and tenant (full replace
of which dataset(s) are designated for federated search).
Sets which dataset is used for federated search when queries omit dataset names.
If datasetIds is non-empty, the first ID selects the federated search dataset
and any previous one is cleared. If datasetIds is an empty array, the
federated search dataset is cleared for this account and tenant.