fix: Audit Log records don't get created with threaded task processing

[khvn26]

Closes #2949

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Changes

• Wrapped threaded task runs in transaction.on_commit by default, made it configurable
• Added docs, functioning typing
• Added debug logging for all webhook errors

How did you test this code?

Unit tests cover the new code paths.
IDE (VSCode + pylance) highlights the task handler methods and attributes correctly.

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Name	Status	Preview	Comments	Updated (UTC)
docs	🛑 Canceled (Inspect)			Nov 13, 2023 11:14am
flagsmith-frontend-preview	🛑 Canceled (Inspect)			Nov 13, 2023 11:14am
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[github-actions]

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[codecov-commenter]

Codecov Report

Attention: 1 lines in your changes are missing coverage. Please review.

Comparison is base (8eedf55) 95.64% compared to head (a291cb4) 95.65%.
Report is 6 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #2958   +/-   ##
=======================================
  Coverage   95.64%   95.65%           
=======================================
  Files        1012     1012           
  Lines       29181    29220   +39     
=======================================
+ Hits        27911    27949   +38     
- Misses       1270     1271    +1     

Files	Coverage Δ
api/app/settings/common.py	88.19% <ø> (ø)
api/task_processor/decorators.py	100.00% <100.00%> (ø)
api/webhooks/webhooks.py	95.45% <100.00%> (+0.33%)	⬆️
...k_processor/test_unit_task_processor_decorators.py	93.45% <96.15%> (+0.51%)	⬆️

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