/// <summary>
/// Selects a top level value from the json user data with the given key name and adds it as a Claim.
/// This no-ops if the ClaimsIdentity already contains a Claim with the given ClaimType.
/// This no-ops if the key is not found or the value is empty.
/// </summary>
/// <param name="collection"></param>
/// <param name="claimType">The value to use for Claim.Type when creating a Claim.</param>
/// <param name="jsonKey">The top level key to look for in the json user data.</param>
public static void MapUniqueJsonKey(this ClaimActionCollection collection, string claimType, string jsonKey)
{
collection.MapUniqueJsonKey(claimType, jsonKey, ClaimValueTypes.String);
}