[WIP]fix: preserve soft-delete flags in workflow task ACK writes.

[leozhang2018]

What this PR does / Why we need it:

The workflow controller loads a WorkflowTask document into memory at startup and holds a reference (c.workflowTask) for the entire lifetime of the run. When a workflow is deleted while a task is still executing, DeleteWorkflowV4 soft-deletes all associated task documents by setting is_deleted: true and is_archived: true in MongoDB.

However, updateWorkflowTask (the ACK callback invoked after every job/stage transition) writes the full in-memory task object back to MongoDB using $set. Because the in-memory object was loaded before the workflow was deleted, its IsDeleted and IsArchived fields are both false. Every ACK call therefore silently undoes the soft-delete, resetting is_deleted to false and making the task reappear in the UI as "running" — even after the workflow has been removed.

This also meant that a soft-deleted task could never be cleared by InitQueue on service restart (which queries InCompletedTasks filtered by is_deleted: false), nor by any automatic cleanup path, leaving a permanent "zombie" running indicator for users.

What is changed and how it works?

Before writing the in-memory task back to MongoDB, sync IsDeleted and IsArchived from the freshly-read database copy (taskInColl) that is already fetched at the top of updateWorkflowTask. This ensures that a soft-delete performed concurrently (e.g., by DeleteWorkflowV4) is never overwritten by a stale ACK.

Does this PR introduce a user-facing change?

• API change
• database schema change
• upgrade assistant change
• change in non-functional attributes such as efficiency or availability
• fix of a previous issue

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