Worker deployment set-current-version cannot switch to unversioned in default namespace: "BuildID cannot be empty" (Server 1.30.1 / CLI 1.6.1)

Environment

• Date: 2026-03-19
• Temporal Server: 1.30.1
• Temporal CLI (admin-tools): 1.6.1
• Temporal UI: 2.45.3
• Namespace: default
• Deployment: falcon-risk-worker
• Build ID: v20260318112554

Problem

We accidentally created worker deployment metadata in default namespace and tried to clean it up.
Cleanup is blocked because we cannot switch current version to unversioned.

Reproduction

temporal worker deployment set-current-version \
  --deployment-name falcon-risk-worker \
  --unversioned \
  --allow-no-pollers \
  -n default \
  --address 127.0.0.1:7233 \
  -y

Also fails with:

temporal worker deployment set-current-version \
  --deployment-name falcon-risk-worker \
  --build-id "" \
  --allow-no-pollers \
  -n default \
  --address 127.0.0.1:7233 \
  -y


##Actual result
error setting the current worker deployment version: BuildID cannot be empty

##Expected result
--unversioned or --build-id "" should switch current version to unversioned, so delete-version and delete deployment can proceed.

##Impact
Official cleanup flow is blocked for mistaken deployment metadata in default.

##Workaround used
We force-cleaned by terminating/deleting the internal worker deployment entity workflows (workflow-id targeted), then verified:
temporal worker deployment list -n default returns no records.

Start by reproducing the temporal worker deployment set-current-version commands with --unversioned and --build-id "" in the default namespace. Trace the CLI and server handling of the unversioned current version, then verify that the command succeeds and allows the documented delete-version and delete-deployment cleanup flow.