Fix stopping Terraform tasks in waiting_confirmation stage

[JulianKap]

PR Title

Fix task stopping behavior for terraform tasks in waiting_confirmation state

Description

This PR fixes incorrect task status handling when attempting to stop tasks that are in the waiting_confirmation state.
Additionally, a bug was fixed where tasks would fail to stop at the waiting_confirmation stage (except in force stop mode).

Observed problem

When trying to stop a task that is waiting for confirmation (for example during Terraform workflows), the task could not be stopped normally.

UI behavior

When clicking Stop for a task in waiting_confirmation:

1. The task briefly transitioned to stopping.
2. For about 1–2 seconds the Force Stop button appeared.
3. After that the task returned back to waiting_confirmation and the original confirmation buttons reappeared.

As a result, the normal stop operation did not work.
The only reliable way to stop the task was - quickly pressing Force Stop in the UI before the status reverted.

Root cause (Issue 1)

The runner periodically sends task statuses to the server.

When a user attempted to stop a task:

1. The server changed the task status to stopping.
2. Before the stopping logic was processed, the runner sent its current task status waiting_confirmation.
3. This status overwrote the stopping state on the server.

As a result, the task reverted back to waiting_confirmation, making normal stopping impossible.

Root cause (Issue 2 – Terraform specific)

At the waiting_confirmation stage, when a task transitioned to the stopping status, the infinite loop of waiting for confirmation or aborting the task execution was not exited.

As a result, the task at the stopping stage could not transition to the stopped status.

Solution

This PR fixes both issues:

1. Prevents the runner from overwriting the stopping state with waiting_confirmation.
2. Correctly handles stopping logic for tasks that are waiting for confirmation, especially for Terraform workflows where no active process exists at that stage.

Result

• Tasks in waiting_confirmation can now be stopped normally
• The stopping state is no longer overwritten by runner status updates
• UI behavior is now consistent and predictable