ci: unset GITLAB_FEATURES envvar to not bust xargs(1) limits

Hi,

this patch series fixes another issue that we saw creeping into GitLab CI jobs for MSVC+Windows. The root cause is that our environment variables have grown too large, and thus xargs(1) was hitting an assert.

Thanks!

Patrick

To: git@vger.kernel.org

--- b4-submit-tracking ---

This section is used internally by b4 prep for tracking purposes.

{ "series": { "revision": 1, "change-id": "20260302-pks-msvc-meson-xargs-c4bc35496078", "prefixes": [] } }

Closes Windows CI jobs fail with `"bc_ctl.arg_max >= ... (#676 - closed).