settingsGistIdの値が不正な場合、500エラーになる

[MH4GF]

背景

問い合わせをいただいた

github-nippouでrunを押したらこういうエラーが出たのですが、どうしたら良いでしょうか:ぐる目顔:
github-nippou-web.vercel.app/:1
       Failed to load resource: the server responded with a status of 500 ()
786-3264ade908fd4734.js:1 Error: An error occurred in the Server Components render. The specific message is omitted in production builds to avoid leaking sensitive details. A digest property is included on this error instance which may provide additional details about the nature of the error.
window.console.error

VercelのServer Componentのログ
サーバーから返却されるレスポンスがおかしいっぽい 👀

SyntaxError: Unexpected token I in JSON at position 0
    at JSON.parse (<anonymous>)
    at parseJSONFromBytes (node:internal/deps/undici/undici:6662:19)
    at successSteps (node:internal/deps/undici/undici:6636:27)
    at node:internal/deps/undici/undici:1236:60
    at node:internal/process/task_queues:140:7
    at AsyncResource.runInAsyncScope (node:async_hooks:203:9)
    at AsyncResource.runMicrotask (node:internal/process/task_queues:137:8)
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

apiのログ
gistの取得にエラーが出ている 👀

Oct 20 04:04:33 PM  {"time":"2023-10-20T07:04:33.276316272Z","level":"ERROR","msg":"GET https://api.github.com/gists/@[問い合わせいただいた方のユーザー名]: 404 Not Found []"}

→ gistIdの入力フォームを空にしてRunを押してもらうと動いた

概要

gistの取得で404になった場合、適切なエラーメッセージを返したい