Run each scan as their own task so they can raise exceptions without stopping all others at same update period

[GDYendell]

Currently scans with the same update period are batched into one background task. Scan tasks raise exceptions to report errors and stop the update loop from running and erroring repeatedly, but this also stops the other scans in the same task.

We should create separate tasks for every scan even if they are the same update period.

Acceptance Criteria

• Exceptions can be raised in scan tasks without stopping any other scan task