message: Update convertToSpend to fix a bug with decimal conversion
diff: import BigNumber from 'bignumber.js';
  import { isNil } from 'lodash';
  -import { multiply } from './arithmetic';
  +import { multiply, divide } from './arithmetic';
  import { isZero } from './comparison';
  import { roundAmountToNativeCurrencyDecimals } from './rounding-and-approximation';
  import { BigNumberish } from './types';
  +import { convertStringToNumber } from './type-conversion';
  /**
  * Converts a human-readable amount to an amount friendly for specifying on-chain transactions.
  @@ -84,5 +85,9 @@ export const spendToUsd = (amountInSpend: number): number | undefined => {
  * @returns integer spend amount
  */
  export const convertToSpend = (amount: number, currency: string, usdRate: number) => {
  - return Math.ceil(Number(roundAmountToNativeCurrencyDecimals(amount, currency)) / usdRate / SPEND_TO_USD_RATE);
  + return Math.ceil(
  + convertStringToNumber(
  + divide(divide(roundAmountToNativeCurrencyDecimals(amount, currency), usdRate), SPEND_TO_USD_RATE)
  + )
  + );
  };
  