[Backport 2.x] Update unsigned_long API specification tests baseline to 2.8.0

[opensearch-trigger-bot]

Backport 0d3c61d from #7481.

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/15140/
• CommitID: 32693b7
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/15149/
• CommitID: 32693b7
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/15179/
• CommitID: 32693b7

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/15181/
• CommitID: d3a020e
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: FAILURE ❌
• URL: https://build.ci.opensearch.org/job/gradle-check/15182/
• CommitID: 238fb76
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure a flaky test unrelated to your change?

[reta]

Gradle Check (Jenkins) Run Completed with:

* **RESULT:** FAILURE x

* **URL:** https://build.ci.opensearch.org/job/gradle-check/15182/

* **CommitID:** [238fb76](https://github.com/opensearch-project/OpenSearch/commit/238fb76c5bf41c3f486f6fab0bad434f614d0866)
  Please examine the workflow log, locate, and copy-paste the failure(s) below, then iterate to green.
  Is the failure [a flaky test](https://github.com/opensearch-project/OpenSearch/blob/main/DEVELOPER_GUIDE.md#flaky-tests) unrelated to your change?

#7327

[github-actions]

Gradle Check (Jenkins) Run Completed with:

• RESULT: SUCCESS ✅
• URL: https://build.ci.opensearch.org/job/gradle-check/15183/
• CommitID: 238fb76