Deprecate on event and replace it with app lifespan

[northwestwitch]

Description

Changed

• Closes [deprecatiob] on_event is deprecated, use lifespan event handlers instead. #133

How to test

• Launch the app locally

Review

• Tests executed by CR
• "Merge and deploy" approved by
  Thanks for filling in who performed the code review and the test!

This version is a

• MAJOR - when you make incompatible API changes
• MINOR - when you add functionality in a backwards compatible manner
• PATCH - when you make backwards compatible bug fixes or documentation/instructions

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 80.00000% with 1 line in your changes missing coverage. Please review.

Project coverage is 95.25%. Comparing base (123ee47) to head (3d1a7b6).
Report is 26 commits behind head on main.

Files with missing lines	Patch %	Lines
preClinVar/main.py	80.00%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #140      +/-   ##
==========================================
- Coverage   95.30%   95.25%   -0.05%     
==========================================
  Files          11       11              
  Lines         490      506      +16     
==========================================
+ Hits          467      482      +15     
- Misses         23       24       +1     

Flag	Coverage Δ
unittests	95.25% <80.00%> (-0.05%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

---

🚨 Try these New Features:

• Flaky Tests Detection - Detect and resolve failed and flaky tests

[northwestwitch]

Tested locally: 🆗