Revert PIP_ROOT_USER_ACTION changes (ineffective for setup-python)

The pip root-user warning originates from actions/setup-python's
internal ensurepip call, which deliberately strips all PIP_* env vars
(CPython design, see python/cpython#139363). Neither container.env
nor job-level env can suppress it. See PR comment for full analysis.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: leofang

.github/workflows/coverage.yml

@@ -43,10 +43,6 @@ jobs:
       HOST_PLATFORM: "linux-64"
       ARCH: "x86_64"
       CUDA_VER: ${{ needs.coverage-vars.outputs.CUDA_VER }}
-      # Suppress pip warnings in container jobs running as root.
-      # This must be at the job level (not container.env) so that actions
-      # running on the host (e.g. setup-python's internal pip upgrade) also see it.
-      PIP_ROOT_USER_ACTION: "ignore"
     # Our self-hosted runners require a container
     # TODO: use a different (nvidia?) container
     container:

.github/workflows/test-wheel-linux.yml

@@ -78,11 +78,6 @@ jobs:
     runs-on: "linux-${{ matrix.ARCH }}-gpu-${{ matrix.GPU }}-${{ matrix.DRIVER }}-${{ matrix.GPU_COUNT }}"
     # The build stage could fail but we want the CI to keep moving.
     if: ${{ github.repository_owner == 'nvidia' && !cancelled() }}
-    env:
-      # Suppress pip warnings in container jobs running as root.
-      # This must be at the job level (not container.env) so that actions
-      # running on the host (e.g. setup-python's internal pip upgrade) also see it.
-      PIP_ROOT_USER_ACTION: "ignore"
     # Our self-hosted runners require a container
     # TODO: use a different (nvidia?) container
     container: