Retrieves the allowance of a specified ERC20 token for a given owner and spender.
Interface representing the structure of an API response for ERC20 operations.
GET //erc20/{account}/allowance HTTP/1.1 Host: beta.usemoon.ai Authorization: text Accept: */*
A promise that resolves to an ERC20APIResponse containing the allowance as a string.
{ "success": true, "message": "text", "data": "text" }