refactor!: Remove `json-bigint`

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

We can use native `bigint`s via the JSON.parse [reviver](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/JSON/parse) parameter and essentially check via:

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

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

```

Improves on:
- https://github.com/googleapis/gcp-metadata/pull/74
- https://github.com/googleapis/gcp-metadata/pull/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

Start by searching the repository for imports and package declarations for `json-bigint` and `@types/json-bigint`, then identify the JSON parsing entry points that depend on them. Replace those uses with the native JSON.parse reviver approach described in the issue, remove both dependencies, and run the affected tests or repository checks to confirm large integers remain precise.

Scritto dal modello di indicizzazione a partire dal testo della issue.