fix: use latest pet (microsoft#25287)

Author: eleanorjboyd

build/azure-pipeline.stable.yml

@@ -128,7 +128,7 @@ extends:
             project: 'Monaco'
             definition: 593
             buildVersionToDownload: 'latestFromBranch'
-            branchName: 'refs/heads/release/2025.8'
+            branchName: 'refs/heads/release/2025.10'
             targetPath: '$(Build.SourcesDirectory)/python-env-tools/bin'
             artifactName: 'bin-$(buildTarget)'
             itemPattern: |