fix(custom-blocks): include workspaceId in publishCustomBlock return

The publish path builds a CustomBlockWithInputs literal; it was missing
the workspaceId field added to the interface, breaking the type check.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017ddpeoz81CSqYQ73Dzf7yo

Author: TheodoreSpeaks

apps/sim/lib/workflows/custom-blocks/operations.ts

@@ -389,6 +389,7 @@ export async function publishCustomBlock(params: {
     organizationId,
     workflowId,
     workflowName: wf.name,
+    workspaceId: wf.workspaceId,
     workspaceName: ws?.name ?? null,
     type,
     name,