[chore] update torch version to 2.9 (#12969)

Co-authored-by: Baizhou Zhang <sobereddiezhang@gmail.com>

.github/workflows/pr-test-pd-router.yml

@@ -137,7 +137,7 @@ jobs:
       run: |
         echo "Installing SGLang with all extras..."
         python3 -m pip --no-cache-dir install --upgrade pip
-        python3 -m pip --no-cache-dir install torch==2.8.0 torchvision torchaudio --index-url https://download.pytorch.org/whl/test/cu128
+        python3 -m pip --no-cache-dir install torch==2.9.1 torchvision torchaudio --index-url https://download.pytorch.org/whl/test/cu128
         python3 -m pip --no-cache-dir install -e "python[all]" --break-system-packages
         python3 -m pip --no-cache-dir install mooncake-transfer-engine==0.3.7.post2
         python3 -m pip --no-cache-dir install --user --force-reinstall genai-bench==0.0.2

.github/workflows/pr-test.yml

@@ -380,7 +380,6 @@ jobs:
       - name: Install dependencies
         run: |
           CUSTOM_BUILD_SGL_KERNEL=${{needs.check-changes.outputs.sgl_kernel}} bash scripts/ci/ci_install_dependency.sh diffusion
-
       - name: Run diffusion server tests
         timeout-minutes: 60
         run: |