fix: cancelling session from sessions service cancel tasks and abort results from the session

[aneojgurhem]

Motivation

Previously, cancelling a session from sessions service was only updating the session status, leaving all its submitted and running tasks in autoscaling count. This PR removes tasks of a cancelled session from the autoscaling count by cancelling of the tasks and results from the session.

Description

When calling the Cancel RPC from the session service, we also change task and results statuses in the cancelled session.

Testing

On an ArmoniK instance, this new implementation was used and confirmed to change the statuses.

Impact

• It will reduce the computing resources consummed because the submitted tasks from a cancelled session will change status to cancelling and not count for autoscaling.
• If previously cancelling tasks are not removed from the queue during downscaling, when a new session is submitted and upscaling occurs, cancelling tasks will be removed first from the queue storage before new tasks will be processed (at equal priority).

Checklist

• My code adheres to the coding and style guidelines of the project.
• I have performed a self-review of my code.
• I have commented my code, particularly in hard-to-understand areas.
• I have made corresponding changes to the documentation.
• I have thoroughly tested my modifications and added tests when necessary.
• Tests pass locally and in the CI.
• I have assessed the performance impact of my modifications.