replaces on_event with lifespan event handlers

[anthonyduong9]

Problem

• When inference tests are run, the DeprecationWarning
on_event is deprecated, use lifespan event handlers instead. shows up in the logs.
• In autointerp, we suppress the error with # type: ignore[deprecated].

Fix

• Removing on_event functions.
• Creating lifespan() functions and passing them to FastAPI.lifespan.

Testing

• From apps/inference, I ran poetry run python start.py, and made several requests to POST /tokenize.
• From apps/autointerp, I ran poetry run uvicorn server:app --host 0.0.0.0 --port 5003 --workers 1 and made requests to each endpoint besides for POST /score/embedding.

Fixes #70

[codecov]

Codecov Report

❌ Patch coverage is 65.11628% with 15 lines in your changes missing coverage. Please review.
✅ Project coverage is 7.92%. Comparing base (e8ddd08) to head (9cd85c0).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
apps/inference/neuronpedia_inference/server.py	71.42%	8 Missing ⚠️
apps/autointerp/neuronpedia_autointerp/logging.py	0.00%	7 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##            main     #87      +/-   ##
========================================
+ Coverage   7.86%   7.92%   +0.06%     
========================================
  Files        124     125       +1     
  Lines      17470   17505      +35     
  Branches     381     381              
========================================
+ Hits        1374    1388      +14     
- Misses     16085   16106      +21     
  Partials      11      11              

Flag	Coverage Δ
autointerp	80.00% <0.00%> (-20.00%)	⬇️
inference	36.79% <77.77%> (+0.01%)	⬆️
webapp	5.18% <ø> (+0.06%)	⬆️

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[hijohnnylin]

Sorry for the delay in getting around to this.

The cost-benefit doesn't work out currnetly for this change: it eliminates a deprecation warning in the code, but it will be a heavy lift to test this in production (Kubernetes/GoogleCloud is slow, plus resolving issues could take a significant amount of time debugging).