Implement kill action requests on scheduler

[zbirenbaum]

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Description

Implements scheduler api for sending a kill action request to a worker. Allows for action cancellation during scenarios such as client disconnection.

towards #338

Type of change

• [x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Adds new test to confirm that the worker receives the kill action request

Checklist

• [x] Updated documentation if needed
• [x] Tests added/amended
• [x] bazel test //... passes locally
• [x] PR is contained in a single commit, using git amend see some docs

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This change is 

[notion-workspace[bot]]

Scheduler API for Kill Action

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