[BUG]GetPullRequest Endpoint returned data not as specified

### API Spec link

https://learn.microsoft.com/en-us/rest/api/azure/devops/git/pull-requests/get-pull-request?view=azure-devops-rest-7.1

### API Spec version

7.1

### Describe the bug

despite the includeCommits option being passed along as "true" there is no detailed information about the commits available (only links to the commit; no Change count dictionary; no gitchange object...)

### Expected behavior

as specified

### Actual behavior

this is one example entry in the pullRequestsFromForkExtended list that is generated in the code snippet in the reproduction steps

```
{'repository': {'id': 'cdebd4b6-9bfa-4218-bb64-2daea2d2d543', 'name': 'tracabilityMapAndMetricsGenerator.Fork3', 'url': 'https://dev.azure.com/Clarios/680dfb46-9cac-413f-9ab1-57a87a6f63ac/_apis/git/repositories/cdebd4b6-9bfa-4218-bb64-2daea2d2d543', 'project': {...}, 'size': 32042, 'remoteUrl': 'https://Clarios@dev.azure.com/Clarios/SW_Tools/_git/tracabilityMapAndMetricsGenerator.Fork3', 'sshUrl': 'git@ssh.dev.azure.com:v3/Clarios/SW_Tools/tracabilityMapAndMetricsGenerator.Fork3', 'webUrl': 'https://dev.azure.com/Clarios/SW_Tools/_git/tracabilityMapAndMetricsGenerator.Fork3', 'isFork': True, 'isDisabled': False, 'isInMaintenance': False}, 'pullRequestId': 39888, 'codeReviewId': 39888, 'status': 'completed', 'createdBy': {}, 'creationDate': '2025-11-26T10:42:34.2763747Z', 'closedDate': '2025-11-26T10:45:02.4820572Z', 'title': 'merge branch from fork2 into fork3', 'description': 'Updated pyproject.toml', 'sourceRefName': 'refs/pull/39888/source', 'targetRefName': 'refs/heads/master', 'mergeStatus': 'succeeded', 'isDraft': False, 'mergeId': '569ea276-b697-4e6d-905d-b0d169bac49f', 'lastMergeSourceCommit': {'commitId': '858c1edcd72a98cd70c8c7e4b36e4fb96ff58cd8', 'url': 'https://dev.azure.com/Clarios/680dfb46-9cac-413f-9ab1-57a87a6f63ac/_apis/git/reposito...s/858c1edcd72a98cd70c8c7e4b36e4fb96ff58cd8'}, 'lastMergeTargetCommit': {'commitId': '8899da63e280371ea73078096f0740c12f4fa8c4', 'url': 'https://dev.azure.com/Clarios/680dfb46-9cac-413f-9ab1-57a87a6f63ac/_apis/git/reposito...s/8899da63e280371ea73078096f0740c12f4fa8c4'}, 'lastMergeCommit': {'commitId': '0fe61047718abff63d983ac6ae7e44bb15b48028', 'author': {...}, 'committer': {...}, 'comment': 'Merged PR 39888: merge branch from fork2 into fork3', 'commentTruncated': True, 'url': 'https://dev.azure.com/Clarios/680dfb46-9cac-413f-9ab1-57a87a6f63ac/_apis/git/reposito...s/0fe61047718abff63d983ac6ae7e44bb15b48028'}, 'reviewers': [], 'url': 'https://dev.azure.com/Clarios/680dfb46-9cac-413f-9ab1-57a87a6f63ac/_apis/git/reposito...-4218-bb64-2daea2d2d543/pullRequests/39888', '_links': {'self': {...}, 'repository': {...}, 'workItems': {...}, 'sourceBranch': {...}, 'targetBranch': {...}, 'statuses': {...}, 'sourceCommit': {...}, 'targetCommit': {...}, 'mergeCommit': {...}, 'createdBy': {...}, 'iterations': {...}}, 'completionOptions': {'mergeCommitMessage': 'Merged PR 39888: merge branch from fork2 into fork3\n\nUpdated pyproject.toml', 'mergeStrategy': 'noFastForward', 'autoCompleteIgnoreConfigIds': [...]}, 'supportsIterations': True, 'completionQueueTime': '2025-11-26T10:45:01.7243348Z', 'closedBy': {}, 'artifactId': 'vstfs:///Git/PullRequestId/680dfb46-9cac-413f-9ab1-57a87a6f63ac%2fcdebd4b6-9bfa-4218-bb64-2daea2d2d543%2f39888', 'forkSource': {'repository': {...}, 'name': 'refs/heads/branch1', 'objectId': None, 'creator': None, 'url': None}}
```

### Reproduction Steps

assume the following python snippet
```
pullRequests.extend(applicationContext.devops.getAllPullRequests(repositoryID, extraQueryOptions=[("searchCriteria.status", "all")]))

pullRequestsFromFork = list(filter(lambda x: "forkSource" in x.keys(), pullRequests))
pullRequestsFromForkExtended = []
for i in range(0, len(pullRequestsFromFork)):
pullRequestsFromForkExtended.append(applicationContext.devops.getPullRequest(pullRequestsFromFork[i]["pullRequestId"], pullRequestsFromFork[i]["repository"]["id"], extraQueryOptions=[("includeCommits", "true"), ("includeWorkItemRefs", "true")]))
```
where the functions are defined as
```
def getPullRequest(self, pullRequestID : int, repositoryID : str, project : Optional[str] = "", extraQueryOptions : Optional[list[tuple[str, Any]]] = []):
return self._synchronizedExec(self.getPullRequestAsync(pullRequestID, repositoryID, project))

async def getPullRequestAsync(self, pullRequestID : int, repositoryID : str, project : Optional[str] = "", extraQueryOptions : Optional[list[tuple[str, Any]]] = []):
response = await self._performAsyncRequestWithRetries(
self.httpxClient.get,
self._urlFactory(
f"{project}/_apis/git/repositories/{repositoryID}/pullrequests/{pullRequestID}",
[("api-version", self.usedAPIVersion)] + extraQueryOptions
)
)
return response.json()
```

### Environment

_No response_

Start with the linked Microsoft Azure DevOps Get Pull Request API specification, version 7.1, and the shown Python getPullRequestAsync call. Compare the response returned with includeCommits=true against the documented schema, then confirm whether the specification or the reported behavior needs correction; done means the discrepancy has a clearly supported resolution.

Written by the indexing model from the issue text.