1. 1. Proposed changes

• Update `evergreen/activate_task.py` to call Evergreen’s `activate_version_tasks` endpoint when a configured task is missing from a non-patch build.
• Preserve existing idempotent activation, patch scheduling, task-name overrides, commit-queue handling, and skip controls.
• Add regression coverage in `buildscripts/tests/test_activate_task.py`.

1. 1. Operational benefit

Prevents `archive_dist_test` from failing solely because `archive_dist_test_debug` has not yet been materialized on waterfall or cron builds, preserving the debug-symbol availability guarantee.

1. 1. Testing

• `bazel test --test_output=errors //buildscripts/tests:test_activate_task`
• `bazel run format`

1. 1. Safety and compatibility

Existing-task activation and patch scheduling paths are unchanged; the new path validates the build variant and version expansions before making the API call.