Pin pytorch/pytorch to release/2.13 in windows validation

The windows smoke test reads the expected cuDNN version from pytorch/pytorch's
.ci/pytorch/windows/internal/cuda_install.bat. validate-windows-binaries.yml
checked out pytorch/pytorch at main (EXPECTED_CUDNN_VERSION=9.23.1), while the
release/2.13 binary ships cuDNN 9.20.0, causing:

  RuntimeError: cuDNN version mismatch for CUDA 13.0. Loaded: 9.20.0 Expected: 9.23.1

Pin the ref to release/2.13 (which expects 9.20.0). Mirrors the linux/aarch64
fix already in this release branch.

Author: atalman

.github/workflows/validate-windows-binaries.yml

@@ -110,7 +110,7 @@ jobs:
     with:
       runner: ${{ matrix.package_type == 'libtorch' && 'windows.4xlarge' || matrix.validation_runner }}
       repository: "pytorch/pytorch"
-      ref: main
+      ref: release/2.13
       job-name: ${{ matrix.build_name }}
       binary-matrix: ${{ toJSON(matrix) }}
       timeout: 60