Throw `GitHubProjectInvalidValueError` error when text is too long for text field (1024+ bytes)

### Please avoid duplicates

- [x] I checked [all open bugs](https://github.com/gr2m/github-project/issues?q=is%3Aissue+is%3Aopen+label%3Abug) and none of them matched my problem.

### Reproducible test case

see test/recorded/api.items.add-draft-with-too-long-text/fixtures.json

### Please select the environment(s) that are relevant to your bug report

- [ ] Browsers
- [ ] Node
- [ ] Deno

### Versions

5.3.0, Node v18.18.0

### What happened?

follow up to https://github.com/gr2m/github-project/issues/142. We introduced a workaround via #143, but the problem can still occur.

### Would you be interested in contributing a fix?

- [ ] yes

test/recorded/api.items.add-draft-with-too-long-text/fixtures.jsonから始め、#143で導入された回避策と、#142の追補コンテキストを確認してください。1024+バイトのテキストケースを再現し、APIの失敗が表面化するのではなく、GitHubProjectInvalidValueErrorが発生することを確認してください。

索引モデルが issue の本文から書いたものです。