Fix undefined behaviour error message coming from background tasks

[tegefaulkes]

Specification

When starting an existing agent that hasn't run for a little while we get the following warning logger message.

We'll need to find the cause for this and fix it. There aren't many tasks that persist between restarts so it should be simple to narrow down. But in that vein we need to make the following changes to make these problems more clear.

1. The message should mention which task handler failed.
2. Any usage of utils.never() should include a descriptive message of what shouldn't be happening. so we need to update all usage of never in a task handler.

Additional context

Tasks

1. Update the warning log for a failed task handler to include more information about what task was running.
2. Update the utils.never() usages in task handlers to include proper failure descriptions.
3. Find and determine the failure occurring here and fix it.

[linear]

ENG-400 Fix undefined behaviour error message coming from background tasks