refactor!: Remove json-bigint

[danielbankhead]

Remove json-bigint and @types/json-bigint.

We can use native bigints via the JSON.parse reviver parameter and essentially check via:

const jsonParse = (stringified: string) => JSON.parse(stringified, (key, value, context) => {
  if (Number.isInteger(value) && !Number.isSafeInteger(value)) {
    // Use the context for the appropriate precision
    return BigInt(context.source);
  }

  return value;
});

Example:

const bigJSON = '{"largeNumber": 12345678901234567890, "a": {"b": 1, "c": 893081290390128309213821903 }}';
const res = jsonParse(bigJSON);

// res:
// {
//  largeNumber: 12345678901234567890n,
//  a: { b: 1, c: 893081290390128309213821903n }
// }

Improves on:

• fix: properly handle large numbers in responses #74
• fix: ask gaxios for text and not json #152

Documentation:

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/BigInt/BigInt#using_bigint_to_convert_a_number_to_a_bigint
• https://www.json.org/json-en.html

[d-goog]

Must wait until Node 22:

• https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse#browser_compatibility