`gh pr edit --title` fails when a team reviewer is inaccessible to the token

从 gh pr edit 命令开始，跟踪 PullRequestUpdate mutation 之前对 pull request 的初始查找。使用提供的 team-reviewer 和 limited-token 复现来验证，标题替换不再读取 reviewRequests，同时更新仍能完成。完成标准是标题发生更改，不再出现被禁止的 reviewer 错误，并且现有测试通过。

Describe the bug

gh pr edit --title can fail before performing the update because its initial pull request lookup fetches reviewRequests even though the current reviewers are not needed to replace the title.

This is reproducible when the pull request has a requested team reviewer and the token can update pull requests but cannot resolve that reviewer. The GraphQL response contains the pull request data plus a FORBIDDEN error at:

repository.pullRequest.reviewRequests.nodes.0.requestedReviewer

This is the same general over-fetching problem previously reported in #8784 for projectCards, but the reviewer path remains reproducible in the latest release.

Affected version

gh version 2.99.0 (2026-09-01)
https://github.com/cli/cli/releases/tag/v2.99.0

Steps to reproduce the behavior

1. Use a token that has permission to write pull requests in an organization repository but cannot resolve a requested team reviewer.

2. Choose a pull request authored by the authenticated user that has a team review request.

3. Run:

   GH_TOKEN="$TOKEN" gh pr edit <number> --repo <owner/repo> --title "<current title>"
   

4. Observe that the command exits before updating the pull request.

I also reproduced this with GH_DEBUG=api. The lookup requested reviewRequests(first: 100) and attempted to resolve user, bot, team, and team organization details.

Expected vs actual behavior

Expected: replacing the title should require only enough pull request data to identify the pull request and print its URL. The command should perform the update without reading reviewers.

Actual: the command exits non-zero while resolving an unrelated team reviewer:

GraphQL: Resource not accessible by personal access token (repository.pullRequest.reviewRequests.nodes.0.requestedReviewer)

A query for only the pull request id and url succeeds with the same token. A locally patched build that uses that minimal lookup also completes the real PullRequestUpdate mutation end to end.

Logs

The sanitized GraphQL error is:

{
  "type": "FORBIDDEN",
  "path": [
    "repository",
    "pullRequest",
    "reviewRequests",
    "nodes",
    0,
    "requestedReviewer"
  ],
  "extensions": {
    "saml_failure": false
  },
  "locations": [
    {
      "line": 1,
      "column": 211
    }
  ],
  "message": "Resource not accessible by personal access token"
}

Repository and pull request details have been omitted because the reproduction used a private organization repository.