Remove unnecessary cuda-version from CI matrix

Author: samanklesaria

.github/workflows/unittest-linux-cpu.yml

@@ -14,7 +14,6 @@ jobs:
             matrix:
                 # TODO add up to 3.13
                 python_version: ["3.10"]
-                cuda-version: ["12.6"]
             fail-fast: false
         uses: pytorch/test-infra/.github/workflows/linux_job_v2.yml@main
         permissions: