CI: drop the no-op -e LANG=en_US.UTF-8 container option #5699

Follow-up to #5682 (review comment: #5682 (comment)).

The nrel/openstudio-cmake-tools images used in CI (noble-main amd64 and arm64, almalinux9-main) already set LANG=en_US.UTF-8, LANGUAGE=en_US:en and LC_ALL=en_US.UTF-8 in their image config, so -e LANG=en_US.UTF-8 does nothing.

It appears in incremental-build.yml:50 and full-build.yml:110,124,138. Remove it from all four so the workflows don't drift.