avoid interactive prompts when updating from an environment.yaml

[jameslamb]

Working with @taureandyernv yesterday, we tried something like this to patch in a dependency at run time.

cat > ./environment.yml <<EOF
channels:
- dglteam/label/th23_cu121
dependencies:
- dgl
EOF

docker run \
  --rm \
  -v $(pwd)/environment.yml:/home/rapids/environment.yml \
  -it rapidsai/base:25.02a-cuda12.5-py3.12 \
  conda env export

Found that that prompts for confirmation:

  Package           Version  Build    Channel                       Size
──────────────────────────────────────────────────────────────────────────
  Install:
──────────────────────────────────────────────────────────────────────────

  + dgl    2.4.0.th23.cu121  py312_0  dglteam/label/th23_cu121     295MB

  Summary:
  Install: 1 packages
  Total download: 295MB

──────────────────────────────────────────────────────────────────────────

Confirm changes: [Y/n]

But that prompt seems not to make it through to mamba.

And even if that did work, this interactive prompt prevents the use of the "mount in an environment.yml" approach in situations where you aren't running the container interactively... for example, where you want to use this image in a container in a Kubernetes Pod, and provide an environment.yml via a ConfigMap or file Secret.

This proposes skipping the confirmation and always running mamba env update -y when an environment.yml is provided.

Notes for Reviewers

How I tested this

Pulled an image built from this PR and confirmed that that install pattern described above works and does not prompt for interactive input.

cat > ./environment.yml <<EOF
channels:
- dglteam/label/th23_cu121
dependencies:
- dgl
EOF

docker run \
  --rm \
  -v $(pwd)/environment.yml:/home/rapids/environment.yml \
  -it rapidsai/staging:docker-727-25.02a-cuda12.5-py3.12 \
  conda env export

...
  - dgl=2.4.0.th23.cu121=py312_0
...

[jameslamb]

This is blocked by #726