normalizeCustomersTableAccount = account => {
  const { Id: IdentityId, UserPoolId: UserId, ...rest } = account
  return { IdentityId, UserId, ...rest }
}
"Normalizes" an account item from CustomersTable, by renaming the "Id"
attribute to "IdentityId" and renaming the "UserPoolId" attribute to
"UserId". This makes it consistent with the more intuitive attribute names
in the PreLoginAccountsTable.