fix: fastapi exception handlers not work

[waketzheng]

Description

Fixes #1874

Motivation and Context

starlette (used by fastapi) added a DeprecationWarning for @app.exception_handler:
https://github.com/encode/starlette/blob/a7d0b14c7378aa2e95b0b13583fe0dadace363be/starlette/applications.py#L166

How Has This Been Tested?

PYTHONPATH=examples/fastapi pytest examples/fastapi/_tests.py

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added the changelog accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[codspeed-hq]

CodSpeed Performance Report

Merging #1880 will not alter performance

_{Comparing waketzheng:fix-fastapi-exception-handle (7c05844) with develop (7cb24a5)}

Summary

✅ 12 untouched benchmarks