Refactor and simplify notification logic a bit

[Swatinem]

Also fixes a few type errors while I was at it.

[sentry-autofix]

✅ Sentry found no issues in your recent changes ✅

[giovanni-guidini]

🥔🥔

[codecov-notifications]

Codecov Report

Attention: Patch coverage is 94.44444% with 2 lines in your changes missing coverage. Please review.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
services/notification/__init__.py	96.29%	1 Missing ⚠️
services/notification/commit_notifications.py	66.66%	1 Missing ⚠️

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[codecov]

Codecov Report

Attention: Patch coverage is 94.44444% with 2 lines in your changes missing coverage. Please review.

Project coverage is 97.71%. Comparing base (e932541) to head (8e70aab).
Report is 2 commits behind head on main.

✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
services/notification/__init__.py	96.29%	1 Missing ⚠️
services/notification/commit_notifications.py	66.66%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1185      +/-   ##
==========================================
- Coverage   97.71%   97.71%   -0.01%     
==========================================
  Files         455      455              
  Lines       37205    37200       -5     
==========================================
- Hits        36354    36349       -5     
  Misses        851      851              

Flag	Coverage Δ
integration	42.76% <77.77%> (-0.01%)	⬇️
unit	90.54% <94.44%> (-0.01%)	⬇️

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[sentry-io]

Suspect Issues

This pull request was deployed and Sentry observed the following issues:

• ‼️ KeyError: 'type' app.tasks.notify.Notify View Issue

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